100525 + Interview Questions in GENERAL QA IN GENERAL AWARENESS Page 1938 InterviewSolution

96851.	This is the watch ________ does not work properly. A) who B) that C) it D) she
Answer» Correct option is B) that

Discussion

96852.	Where is the girl ________ saw the accident? A) whom B) his C) she D) who
Answer» Correct option is D) who

Discussion

96853.	This is the watch ________ does not work properly. A) who B) that C) it D) his
Answer» Correct option is B) that

Discussion

96854.	These houses _____ by settlers many years ago. A) are maid B) were built C) built D) made
Answer» Correct option is B) were built

Discussion

96855.	The computer ________ guaranteed by the company. A) is B) are C) it’s D) aren’t
Answer» Correct option is A) is

Discussion

96856.	Where is the girl ________ saw the accident? A) whom B) her C) she D) who
Answer» Correct option is D) who

Discussion

96857.	These houses ________ by settlers many yeas ago. A) are made B) were built C) built D) made
Answer» Correct option is B) were built

Discussion

96858.	Flux `(ph)` as a function of distance `(r)` from centre of uniformly charged solid sphere of charge `Q` and radius `R`, is best represented byA. B. C. D.
Answer» Correct Answer - C for inside `rltR` `phi=(Q_("in"))/(epsilon_(0))=Q/((R^(3))/(epsilon_(0))) r^(3)` for `rgtRphi=(Q_("in"))/(epsilon_(0))=Q/(epsilon_(0))`

Discussion

96859.	Block M slide donw on frictionless inclined plane as shown. Find frictional force acting on block m while it is at rest with respect to the block M. `(m=2kg, M=5kg,g=10m//sec^(2))` A. 8.5NB. 9.6NC. 12.8ND. 16.5N
Answer» `a= g sin 37^(@)` `f=mxxaxxcos 37^(@)`

Discussion

96860.	A positively charged particle starts at rest 25 cm from a second positively charged particle, which is held stationary throughout the experiment. The first particle is released and accelerates directly away from the second particle. When the first particle has moved 25 cm, it has reached a velocity of `10(sqrt2)ms^(-1)` . What is the maximum velocity `(in xx 10 ms^(-1))` that the first particle will reach?
Answer» `kq^(2)((1)/(r)-(1)/(2r))=(1)/(2)m(v^(2))` or `(kq^(2))/(2r)=(1)/(2)mV^(2)` or `(kq^(2))/(r)=(1)/(2)m(sqrt(2v))^(2)=(1)/(2)m(V_("max")^(2))` or `V_("max")=Vsqrt(2)=(10sqrt(2))sqrt(2)=20ms^(-1)=2xx10ms^(-1)`

Discussion

96861.	The resultant ampiltude of a vibrating particle by the superposition of the two waves `y_(1) = a sin ( omega t + (pi)/(3)) and y_(2) = a sin omega t` is :A. aB. `sqrt(2)_(a)`C. `2a`D. `sqrt(3)_(a)`
Answer» Correct Answer - D Resultant amplitude `= 2a cos ((pi//3)/(2)) = sqrt(3a)`

Discussion

96862.	Figure shows, in cross section , two solid spheres with uniformly distributed charge throughout their volumes. Each has radius R. Point O lies on a line connecting the centers of the spheres, at radial distance `R//2` from the center of sphere 1. If the net electric field at point P is zero, and `Q_1 is 64muC` and `Q_2 = 8xmuC`, what is the value of x.
Answer» `E_(P)=(kQ_(2))/(((3R)/(2))^(2))-(kQ_(1)(R)/(2))/(R^(3))=0` or `(4)/(9)Q_(2)=(Q_(1))/(2)` or `(Q_(2))/(Q_(1))=(9)/(8)` `thereforeQ_(2)=(9xx64)/(8)=72muC=8xx9muC`

Discussion

96863.	Excess electrons are placed on a small lead sphere of mass `6.90 ` g so that its net charge is `-3.20 xx 10^(-9)C`. Find the number of excess electorns ( in terms of `xx 10^(10))` on the sphere.
Answer» `qq=n_(e)e` or `n_(e)=(-3.20xx10^(-9))/(-1.6xx10^(-9))=2.0xx10^(10)`

Discussion

96864.	The electric field strength depends only on the x, y, and z coordinates according to the law `E = (a(xhati+yhatj+zhatk))/(x^2+y^2+z^2)^3//2`, where ` a = 280 Nm^2C^(-1)` is a constant. If the potential difference between (3,2,6) and (0,3,4) is `x^2`. What is the value of x.
Answer» `vecE=(avecr)/(r^(2))` `V=(-a)/(r)` `triangleV=(a)/(r_(2))-(a)/(r_(1))=(a)/(5)-(a)/(7)=(2a)/(35)=2xx(280)/(35)=16V=4^(2)`

Discussion

96865.	Two mutually perpendicular infinite wires along x-axis and y-axis carry charge densities `lambda_1 and lambda_2`. The electric line of force at P is along the line `y = x//(sqrt3)`, where P is also a point lying on the same line. Find `lambda_2//lambda_1`.
Answer» Net electric field is `vecP` `vecE=vecE_(1)+vecE_(2)` due to vertical wire `vecE_(1)=(lamda_(1))/(2piepsilon_(0)y)` I `+y`-direction `vecE_(2)=(lamda_(2))/(2piepsilon_(0)x)` due to vertical wire in x-direction `tanalpha=(E_(1))/(E_(2))=(lamda_(1)//2piepsilon_(0)y)/(lamda_(2)//2piepsilon_(0)x)` or `(1)/(sqrt(3))=(lamda_(1)x)/(lamda_(2)y)` or `(lamda_(1))/(lamda_(2))=(x)/(y)sqrt(3)` or `(lamda_(1))/(lamda_(2))=3`

Discussion

96866.	Ram Shyam are walking on two perpendicular tracks with speed `3ms^(-1)` and `4 ms^(-1)`, respectively. At a certain moment `(say t = 0s)`, Ram and Shyam are at 20 m and 40 m away from the intersection of tracks, respectively, and moving towards the intersection of the tracks. During the motion the magnitude of velocity of ram with respect to Shyam isA. `1ms^(-1)`B. `4ms^(-1)`C. `5ms^(-1)`D. `7ms^(-1)`
Answer» `V_(R//S)=sqrt(3^(2)+4^(2))=5`

Discussion

96867.	The device in figure is an acceleraometer which is fitted to a car. It consist of a spherical ball, mass 0.08 kg, attached to a pointer which can move horizontally against a fixed scale that gives the acceleration of the car, O indicates zero acceleration. On each side of the ball are attached identical springs, `S_(1)` and `S_(2)`. that are fixed at their ends. The device is enclosed in a rigid transparent housing. The car accelerates towards A. If the car starts from rest at time t=0 and travels along a straight road. The accelerometer readings are recorded in table. `{:("Time//s","Acceleration//ms^(2)"),(0.00-3.00,11.00),(3.00-4.50,7.00),(4.50-7.00,0.00):}` How fast is the car traveling after 7.00 s?A. 33m/sB. 43.5m/sC. 61m/sD. 64.5m/s
Answer» `V=11xx3+7xx1.5=33+10.5=43.05m//`

Discussion

96868.	The device in figure is an acceleraometer which is fitted to a car. It consist of a spherical ball, mass 0.08 kg, attached to a pointer which can move horizontally against a fixed scale that gives the acceleration of the car, O indicates zero acceleration. On each side of the ball are attached identical springs, `S_(1)` and `S_(2)`. that are fixed at their ends. The device is enclosed in a rigid transparent housing. The car accelerates towards A. If the car starts from rest at time t=0 and travels along a straight road. The accelerometer readings are recorded in table. `{:("Time//s","Acceleration//ms^(2)"),(0.00-3.00,11.00),(3.00-4.50,7.00),(4.50-7.00,0.00):}` How far does the car travel in the first 7.00s?A. 57.38mB. 215.62mC. 166.12mD. 106.88m
Answer» `S_(1)=0xx3+(1)/(2)11xx3^(2)=(99)/(2)=49.5m` `V_(1)=11xx3=33m//s` `S^(2)=33xx1.5+(1)/(2)7xx(1.5)^(2)=49.5+7.875` =57.375 `V_(2)=33+7xx1.5=43.5m//s` `S_(3)=43.5xx2.5=108.75` `S_(T)=49.5+57.38+108.75=215.62m`

Discussion

96869.	Who among the following won the 'BBC Sports Personality of the Year 2019' award ?1. Wayne Rooney2. Ben Stokes3. Ken Williamson4. Kylian Mbappé Lottin
Answer» Correct Answer - Option 2 : Ben Stokes The Correct Answer is Ben Stokes. England Cricketer Ben Strokes has won the BBC Sports Personality of the year 2019. He was presented with his award by Princess Royal and former Manchester United and Scotland footballer Denis Law. Wayne Mark Rooney He is an English professional footballer who plays for Championship club Derby County. Kane Stuart Williamson is a New Zealand international cricketer. He is currently the captain of the New Zealand national team in all formats. Kylian Mbappé Lottin He is a French professional footballer who plays as a forward for Ligue 1 club, Paris Saint-Germain, and the France national team.

96869.

Who among the following won the 'BBC Sports Personality of the Year 2019' award ?1. Wayne Rooney2. Ben Stokes3. Ken Williamson4. Kylian Mbappé Lottin

Answer» Correct Answer - Option 2 : Ben Stokes

The Correct Answer is Ben Stokes.

England Cricketer Ben Strokes has won the BBC Sports Personality of the year 2019.
He was presented with his award by Princess Royal and former Manchester United and Scotland footballer Denis Law.

Wayne Mark Rooney
- He is an English professional footballer who plays for Championship club Derby County.
Kane Stuart Williamson is a New Zealand international cricketer.
- He is currently the captain of the New Zealand national team in all formats.
Kylian Mbappé Lottin
- He is a French professional footballer who plays as a forward for Ligue 1 club, Paris Saint-Germain, and the France national team.

Discussion

96870.	If \( \log _{2}\left(a x^{2}+x+a\right) \geq 1 \forall x \in R \), then exhaustive set of values of ' \( a \) ' is:
Answer» \(log_2 (ax^2 + x +a) \ge 1\) ⇒ \(ax^2 + x +a \ge 2^1\) ⇒ \(ax^2 +x +a -2 \ge 0\) Then \(\triangle \le 0\) \(b^2 - 4ac \le 0\) ⇒ \(1 - 4\times a \times (a -2)\le 0\) ⇒ \(4a^2 - 8a \ge 1\) ⇒ \(4a^2 - 8a -1 \ge 0\) ⇒ \(a \in \left(- \infty , \frac{2-\sqrt5}{2}\right] \cup \left[\frac{2 + \sqrt5}{2}, \infty\right)\) ........(1) Also to defined log function, we have \(ax^2 + x +a > 0\) \(\therefore D < 0\) ⇒ \(b^2 - 4ac <0\) ⇒ \(1 - 4 \times a \times a <0\) ⇒ \(4a^2 >1\) ⇒ \(a \in \left(- \infty , \frac12\right)\cup \left(\frac12, \infty\right)\) ......(2) From (1) & (2), we have \(a \in \left(\left(- \infty , \frac{2-\sqrt5}{2}\right] \cup \left[\frac{2 + \sqrt5}{2}, \infty\right)\right)\cup\left(\left(- \infty , \frac{2-\sqrt5}{2}\right] \cup \left[\frac{2 + \sqrt5}{2}, \infty\right)\right)\) ⇒ \(a \in \left(- \infty , \frac{-1}2\right)\cup \left(\frac{2+\sqrt5}{2}, \infty\right)\).

96870.

If \( \log _{2}\left(a x^{2}+x+a\right) \geq 1 \forall x \in R \), then exhaustive set of values of ' \( a \) ' is:

Answer»

\(log_2 (ax^2 + x +a) \ge 1\)

⇒ \(ax^2 + x +a \ge 2^1\)

⇒ \(ax^2 +x +a -2 \ge 0\)

Then \(\triangle \le 0\)

\(b^2 - 4ac \le 0\)

⇒ \(1 - 4\times a \times (a -2)\le 0\)

⇒ \(4a^2 - 8a \ge 1\)

⇒ \(4a^2 - 8a -1 \ge 0\)

⇒ \(a \in \left(- \infty , \frac{2-\sqrt5}{2}\right] \cup \left[\frac{2 + \sqrt5}{2}, \infty\right)\) ........(1)

Also to defined log function, we have

\(ax^2 + x +a > 0\)

\(\therefore D < 0\)

⇒ \(b^2 - 4ac <0\)

⇒ \(1 - 4 \times a \times a <0\)

⇒ \(4a^2 >1\)

⇒ \(a \in \left(- \infty , \frac12\right)\cup \left(\frac12, \infty\right)\) ......(2)

From (1) & (2), we have

\(a \in \left(\left(- \infty , \frac{2-\sqrt5}{2}\right] \cup \left[\frac{2 + \sqrt5}{2}, \infty\right)\right)\cup\left(\left(- \infty , \frac{2-\sqrt5}{2}\right] \cup \left[\frac{2 + \sqrt5}{2}, \infty\right)\right)\)

⇒ \(a \in \left(- \infty , \frac{-1}2\right)\cup \left(\frac{2+\sqrt5}{2}, \infty\right)\).

Discussion

96871.	If \( \log _{2}\left(a x^{2}+x+a\right) \geq 1 \forall x \in R \), then exhaustive set of values of ' \( a \) ' is:
Answer» log₂(ax²+x+a)>=1 => log_e(ax²+x+a)/log_e(2)>=1 => log_e(ax²+x+a)>=log(2) => ax²+x+a>=2 ax²+x+(a-2)>=0 a>0−(i) Δ≤0 1−4a(a−2)≤2 -1-4a²+8a<=0 1-8a+4a²>=0

96871.

If \( \log _{2}\left(a x^{2}+x+a\right) \geq 1 \forall x \in R \), then exhaustive set of values of ' \( a \) ' is:

Answer»

log₂(ax²+x+a)>=1

=> log_e(ax²+x+a)/log_e(2)>=1

=> log_e(ax²+x+a)>=log(2)

=> ax²+x+a>=2

ax²+x+(a-2)>=0

a>0−(i)

Δ≤0

1−4a(a−2)≤2

-1-4a²+8a<=0

1-8a+4a²>=0

Discussion

96872.	In the arrangement shown in Figure 13.4 there are two coils wound on a non-conducting cylindrical rod.Initially the key is not inserted. Then the key is inserted and later removed. Then(a) the deflection in the galvanometer remains zero throughout(b) there is a momentary deflection in the galvanometer but it dies out shortly and there is no effect when the key is removed(c) there are momentary galvanometer deflections that die out shortly; the deflections are in the same direction(d) there are momentary galvanometer deflections that die out shortly; the deflections are in opposite directions
Answer» (d) there are momentary galvanometer deflections that die out shortly; the deflections are in opposite directions

Discussion

96873.	A conducting rod AB moves parallel to x-axis in the x-y plane. A uniform magnetic field B pointing normally out of the plane exists throughout the region. A force F acts perpendicular to the rod, so that the rod moves with uniform velocity v. The force F is given by (neglect resistance of all the wires) A. `(vB^(2)l^(2))/(R)e^(-t//RC)`B. `(vB^(2)l^(2))/(R)`C. `(vB^(2)l^(2))/(R)(1-e^(-t//RC))`D. `(vB^(2)l^(2))/(R)(1-e^(-2t//RC))`
Answer» Correct Answer - C Formation of `PbSO_(4)` is prevented in extraction of lead by carbon reduction

Discussion

96874.	A uniform magnetic field exists in the plane of paper pointing from left to right as shown in Figure 13.3. In the field an electron and a proton move as shown. The electron and the proton experience(a) forces both pointing into the plane of paper(b) forces both pointing out of the plane of paper(c) forces pointing into the plane of paper and out of the plane of paper, respectively(d) force pointing opposite and along the direction of the uniform magnetic field respectively
Answer» The correct option is (a) forces both pointing into the plane of paper. Explanation: Direction of current is taken as opposite to the flow of electron or in the direction of flow of protons. In the given figure, the proton and electron are moving in opposite direction to each other and in perpendicular to the direction of magnetic field. So, current due to both electron and proton are in same direction. Hence, the forces acting on both will be in the same direction. By Fleming's left hand rule the direction force is pointing into the plane of paper.

96874.

A uniform magnetic field exists in the plane of paper pointing from left to right as shown in Figure 13.3. In the field an electron and a proton move as shown. The electron and the proton experience(a) forces both pointing into the plane of paper(b) forces both pointing out of the plane of paper(c) forces pointing into the plane of paper and out of the plane of paper, respectively(d) force pointing opposite and along the direction of the uniform magnetic field respectively

Answer»

The correct option is (a) forces both pointing into the plane of paper.

Explanation:

Direction of current is taken as opposite to the flow of electron or in the direction of flow of protons.

In the given figure, the proton and electron are moving in opposite direction to each other and in perpendicular to the direction of magnetic field. So, current due to both electron and proton are in same direction. Hence, the forces acting on both will be in the same direction. By Fleming's left hand rule the direction force is pointing into the plane of paper.

Discussion

96875.	Which of the following element shows only signle oxidation state in their compound except zero?A. HydrogenB. CarbonC. FluorineD. Oxygen
Answer» (i) H shows-0,+1 and -1 oxidation state (ii) Carbon and oxygen has variable valency (iii) Fluorine shows -1 oxidation state.

Discussion

96876.	Consider the reaction: `P_(4)(s)+F_(2)(g)rarrPF_(3)(g)` How many gram of `F_(2)` are needed to produce 11.2 L of `PF_(3)` at NTP?A. 28.5gmB. 48gmC. 57gmD. 85.5gm
Answer» `P_(4)+6F_(2)rarr4PF_(3)` `11.2` lit of `PF_(3)rArr0.5` mole of `PF_(3)` mole of `F_(2)` required `=(6)/(4)xx0.5=(3)/(4)` moles mass of `F_(2)` required `=(3)/(4)xx38=28-5gm`

Discussion

96877.	Statement (I) : Piston temperature profiles near full load are flattened in case of liquid cooled engines whereas for air cooled engines temperature profiles are steeper. Statement (II) : The piston temperature profiles are different in nature for liquid cooled and air cooled engines because of the different values of ehat capacities.(a) Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I) (b) Both statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I) (c) Statement (I) is true but Statement (II) is false (d) Statement (I) is false but Statement (II) is true
Answer» (d) Statement (I) is false but Statement (II) is true The air cooling system for piston is likewise the fin cooling system in which cooling temperature profile is exponential curve not steeper curve. So, statement I is false. Also, liquid cooling system use convective type of cooling in which curve can not be flatten. As different phenomenon is happening for cooling in two different process because of change in heat transportation media and hence heat capacities of cooling fluid.

96877.

Statement (I) : Piston temperature profiles near full load are flattened in case of liquid cooled engines whereas for air cooled engines temperature profiles are steeper. Statement (II) : The piston temperature profiles are different in nature for liquid cooled and air cooled engines because of the different values of ehat capacities.(a) Both Statement (I) and Statement (II) are individually true and Statement (II) is the correct explanation of Statement (I) (b) Both statement (I) and Statement (II) are individually true but Statement (II) is NOT the correct explanation of Statement (I) (c) Statement (I) is true but Statement (II) is false (d) Statement (I) is false but Statement (II) is true

Answer»

(d) Statement (I) is false but Statement (II) is true

The air cooling system for piston is likewise the fin cooling system in which cooling temperature profile is exponential curve not steeper curve. So, statement I is false. Also, liquid cooling system use convective type of cooling in which curve can not be flatten. As different phenomenon is happening for cooling in two different process because of change in heat transportation media and hence heat capacities of cooling fluid.

Discussion

96878.	A projectile is thrown with a velocity `u_(0)` at an angle `theta` with the horizontal. The ratio of the rate of change of speed w.r.t. time, at highest point to that at the point of projection, isA. `g sin theta`B. `- g sin theta`C. zeroD. g
Answer» Correct Answer - C `(dv)/(dt)` (at the top ) = 0 as tangential acceleration at the top = 0 `(dv)/(dt)` (at the starting point) `= g sin theta` So, required ratio = zero

Discussion

96879.	When an ammter of negligible internal resistance is inserted in series with circuit it reads `1 A` When the voltmeter of very large resistance is connected across `X` it reads `1 V`. When the point `A` and `B` are shorted by a conducting wire, the voltmeter meausres `10 V` across the battery. The internal resistance of the battery is equal to A. zeroB. `0.5 Omega`C. `0.2 Omega`D. `0.1 Omega`
Answer» Correct Answer - C c. ` I = 1A` r is the internal resistance of the battery. `12= (X+Y+r)(1)` Also `1 = (X)(1) or X = 1Omega` Voltage across X (when A and B are shorted) `10 = (12/(X+r)) X or 10 = (12)/(1+r) or 1 +r = 6/5` or `r = 1/5 Omega` .

Discussion

96880.	Find the components of vector `vec(a)=3hat(i)+4hat(j)` along the direction of vectors `hat(i)+hat(j)` & `hat(i)-hat(j)`
Answer» Correct Answer - `7/2(hat(i)+hat(j)), -1/2 (hat(i)-hat(j))` Component along the vector `hat(i)+hat(j)` `=(A cos theta) hat(B)=((vec(A).vec(B)))/B^(2) vec(B)=((3hat(i)+4hat(j)).(hati+hatj))/((sqrt(2))^(2))(hat(i)+hat(j))` `=(3+4)/2(hat(i)+hat(j))=7/2(hat(i)+hat(j))` Component along the velocity `hat(i)-hat(j)` `=(A cos theta) hat(B)=((vec(A).vec(B)))/B^(2)vec(B)=((3hati+4hatj).(hati-hatj)(hati-hatj))/((sqrt(2))^(2))` `=((3-4))/2(hat(i)-hat(j))=-1/2(hat(i)-hat(j))`

Discussion

96881.	A square loop of side 2cm carrying current `I_(0)` is placed in x-y plane in a magnetic field `B= (4hat(i)+3hat(j))` T Find the unit vector along the axis about which it will start rotating. A. `(4hat(j)+3hat(i))/5`B. `(-4hat(j)-3hat(i))/5`C. `(-4hat(j)+3hat(i))/5`D. `(4hat(j)-3hat(i))/5`
Answer» Correct Answer - C Magnetic moment is in divection of - `za^(x)` and`vec(B)=4hat(i)+3hat(j)` `vec(B)=4/5hat(i)+3/5hat(j)` `mu=ivec(A)` `=-(4xx10^(-4)xxI_(0))hat(k)` `hat(tau)=muxxhat(B)` `hat(tau)=4/5hat(j)-3/5hat(i)` Thus the unit vector of the axis is `pm hat(tau)`

Discussion

96882.	Two scales on a voltmeter measure voltage up to `20.0V` and `30.0 V`. The resistance connected in series with the galvanometer is `1680 Omega` for the `20.0 V` scale and `2930 Omega` for the `30.0 V` scale. The resistance of the galvanometer and the full scale current are respectivelyA. `320 Omega and 8 mA`B. `70 Omega and 10 mA`C. `820 Omega and 10mA`D. `0.05mA`
Answer» Correct Answer - D `(1680+r)I=20` `(2930+r)I=30` `2xx2930+2r=3 xx 1680+3r` `r=820`

Discussion

96883.	A charged particle enters into a space and continues to move undeflected. Considering gravitational force also on the particle, in the spaceA. a uniform horizontal electric field and a vertical magnetic field may be presentB. a vertical electric field alone may be presentC. uniform electric field and magnetic field both directed vertically downwards may be presentD. a uniform horizontal magnetic field alone may be present
Answer» Correct Answer - B::C::D If a uniform electric field horizontally, then the particle will experience a force due to that electric field along the horizontal direction and if magnetic field is vertical then the force experienced by the particle due to the magnetic field will also be horizontal. If these two forces are equal and opposite to each other, then they will neutralize each other, but a vertically downward force (weight of the particle) remains unbalanced. Hence the particle will not move undefelected. Hence, the option (a) is wrong. If the electric field is verticle, then the resultant force on the particle will not move underflected. Hence, the option (a) is wrong. If the electric field is vertical, then the resultant force on the particle will be the resultant of `qvec(E) and mvec(g)`. This resultalt can be zero, and if it is zero then particle can move undeflected. Henceoption (b) is correct. If both electric field and magnetic field are vertical, and if velocity is also vertical, then net force acting on the particle can be only vertical, so the particle can move undefleted (without change in direction) in vertical direction. Hence option (c) is correct. If a uniform horizontal magnetic field along exists in the space. and the particle is also moving horizontally but perpendicular to the magnetic field then force exerted by the magnetic field will be vertical. If this force is vertically upwards and is equal to weight of the particle then the resultant force on the particle will be zero. hence, the particle will continue to move with constant velocity. Hence option (d) is correct.

Discussion

96884.	A cell of internal resistance is connected across a resistor. A voltemeter having varible resistance `G` is used to meausre p.d. across resistor. The plot of voltmeter reading `V` against `G` is shown. What is value of external resitor `R` A. `5Omega`B. `4Omega`C. `3 Omega`D. `1 Omega`
Answer» Correct Answer - A `I=(24)/((RG)/(R+G)+1)` `V=24-` potential difference across `1Omega` `=24-1xxI` `V=24-(24)/((1/(1//R)+1/G)+1)` For G rightarrowinfty Rightarrow `1/G rightarrow 0` & `V=20V` `Rightarrow 20=24- (24)/(R+1) Rightarrow R= 5Omega`

Discussion

96885.	Three charged particles are collinear and are in equilibrium, thenA. all the charged particles have the same polartiyB. the equilibrium is unstableC. all the charged particles cannot have the same polarityD. Both (b) and (c ) are correct
Answer» Correct Answer - d If a charge particle is in equilibrium under electrostatic force, then that particle never be in stable equilibrium. Hence option (b) is correct. Since, all charges are in equilibrium so, net force an any one of charges are in equilibrium so, net force on any one of charges should be zero-for this two equal and opposite force will act on any charges. Hence option (c ) is also correct.

Discussion

96886.	Suggest an experiment to produce a rainbow in your classroom.
Answer» Activity to produce a rainbow in classroom : (1) Take a prism and place it on the table near a vertical white wall. (2) Take a thin wooden plank, make a small hole in it and fix it vertically on the table. (3) Place the prism between the wooden plank and wall. (4) Place a white light source behind the hole of the wooden plank. Switch on the light. (5) Adjust the height of the prism such that the light falls on one of the lateral surfaces. (6) Observe the changes in the emerged ray of the prism. (7) Adjust the prism by slightly rotating it till you get an image on the wall. (8) We observe a band of different colours on the wall. (9) These colours are nearly equal to the colours of the rainbow, i.e., VIBGYOR.

96886.

Suggest an experiment to produce a rainbow in your classroom.

Answer»

Activity to produce a rainbow in classroom :

(1) Take a prism and place it on the table near a vertical white wall.

(2) Take a thin wooden plank, make a small hole in it and fix it vertically on the table.

(3) Place the prism between the wooden plank and wall.

(4) Place a white light source behind the hole of the wooden plank. Switch on the light.

(5) Adjust the height of the prism such that the light falls on one of the lateral surfaces.

(6) Observe the changes in the emerged ray of the prism.

(7) Adjust the prism by slightly rotating it till you get an image on the wall.

(8) We observe a band of different colours on the wall.

(9) These colours are nearly equal to the colours of the rainbow, i.e., VIBGYOR.

Discussion

96887.	Which among the above is / are true ?a : Force experienced by a charge moving in magnetic field is qvB. b : Magnetic field is weak at poles. c : Magnetic field lines are open loops. d : Magnetic field lines are open loops.
Answer» a : Force experienced by a charge moving in magnetic field is qvB.

Discussion

96888.	The power delivered by a battery of emf 10 V is 10 W, then what is the current delivered by the battery ?
Answer» The power delivered by a battery of emf 10 V is 10 W, then 1 Ampere is the current delivered by the battery.

Discussion

96889.	A conductor is passing into the page. Guess the direction of the current through the conductor, if the magnetic field is formed as shown in the figure.
Answer» Into the page..

Discussion

96890.	What is the bond angle (HOH) in a water molecule?
Answer» 104°31' is the bond angle (HOH) in a water molecule.

Discussion

96891.	Refractive index of glass relative to water is 9/8 . What is the refractive index of water relative to glass ?
Answer» The refractive index of water relative to glass is 8/9.

Discussion

96892.	Power transfer by a non-ideal cell to an external resistor can be same for two different values. Out of which on value `(K_(1))` is less than internal resistance of cell and another `(R_(2))` is greater than internal resistance of cell then:A. `R_(1)` will give less internal lossB. `R_(1)` will give more battery lifeC. `R_(2)` will give less efficiencyD. `R_(2)` will give more battery life
Answer» Correct Answer - D Internal loss `=i^(2)r` whre `i=(epsilon)/(r+R)` battery life time `=("Battery capacity")/("Curent")`

Discussion

96893.	A glass prism with a refracting angle of `60^(@)` has a refractive index 1.52 for red and 1.6 for violet light. A parallel beam of white is incident on one face at an angle of incident which gives minimum deviation for red light. Find : [Use : `sin(50^(@))=0.760 , sin(31.6^(@))=0.520 , sin (28.4^(@))=0.475 , sin (56^(@))= 0.832 , = 22//7`] The length of the spectrum if it is focussed on a screen by a lens of focal length 100 cm is :A. `(10 pi)/(3) cm`B. `(10 pi)/(3) m`C. `(5 pi)/(3) cm`D. `(5 pi)/(3) m`
Answer» Correct Answer - A If `theta = 100 xx 6xx(pi)/(180)cm=(10 pi)/(3) cm`

Discussion

96894.	When the angle of incidence is greater than critical angle, the light ray is reflected into denser medium at interface".What is the value of angle of refraction, when angle of incidence is equal to critical angle ?
Answer» 90° is the value of angle of refraction, when angle of incidence is equal to critical angle.

Discussion

96895.	Among the above substances, for which substance the rate of rise in temperature is low if same quantity of heat is supplied ?SubstanceSpecific heat (cal /g –°CWater 1 Mercury0.033Copper0.095
Answer» Among the above substances, Water for substance the rate of rise in temperature is low if same quantity of heat is supplied.

Discussion

96896.	Write modern periodic law.
Answer» The physical and chemical properties of elements are the periodic function of the electronic configurations of their atoms.

Discussion

96897.	What do you observe when phenolphthalein solution is added to NaOH solution?
Answer» The NaOH solution turns into pink colour.

Discussion

96898.	The differentiating electron in one atom is '4p1'. (a) Write the set of 3 quantum numbers for it. (b) Write the full electronic configuration of the atom.
Answer» (a) n = 4, l = 1, ml = –1. (b) 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p¹.

96898.

The differentiating electron in one atom is '4p1'. (a) Write the set of 3 quantum numbers for it. (b) Write the full electronic configuration of the atom.

Answer»

(a) n = 4, l = 1, ml = –1.

(b) 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p¹.

Discussion

96899.	Which of the above material is a good conductor ? Why ?Material Resistivity (Ω- m)P1.68 × 10–8Q4.60 × 10–1 R10.0 × 1010
Answer» 'P'. Because it has low resistivity and passes current easily.

Discussion

96900.	Predict the reasons for low melting point for covalent compounds when compared with ionic compounds.
Answer» (1) The melting point is low due to the weak Vander Waal's forces of attractions between the covalent molecules. (2) The force of attraction between the molecules of a covalent compound is very weak. (3) Only a small amount of heat energy is required to break these weak molecular forces, due to which covalent compound have low melting points and low boiling points. (4) Please note that some of the covalent solids like diamond and graphite have, however very high melting points and boiling points.

96900.

Predict the reasons for low melting point for covalent compounds when compared with ionic compounds.

Answer»

(1) The melting point is low due to the weak Vander Waal's forces of attractions between the covalent molecules.

(2) The force of attraction between the molecules of a covalent compound is very weak.

(3) Only a small amount of heat energy is required to break these weak molecular forces, due to which covalent compound have low melting points and low boiling points.

(4) Please note that some of the covalent solids like diamond and graphite have, however very high melting points and boiling points.

Discussion

Explore topic-wise InterviewSolutions in .

This is the watch ________ does not work properly. A) who B) that C) it D) she

Where is the girl ________ saw the accident? A) whom B) his C) she D) who

This is the watch ________ does not work properly. A) who B) that C) it D) his

These houses _____ by settlers many years ago. A) are maid B) were built C) built D) made

The computer ________ guaranteed by the company. A) is B) are C) it’s D) aren’t

Where is the girl ________ saw the accident? A) whom B) her C) she D) who

These houses ________ by settlers many yeas ago. A) are made B) were built C) built D) made

Flux `(ph)` as a function of distance `(r)` from centre of uniformly charged solid sphere of charge `Q` and radius `R`, is best represented byA. B. C. D.

Block M slide donw on frictionless inclined plane as shown. Find frictional force acting on block m while it is at rest with respect to the block M. `(m=2kg, M=5kg,g=10m//sec^(2))` A. 8.5NB. 9.6NC. 12.8ND. 16.5N

The resultant ampiltude of a vibrating particle by the superposition of the two waves `y_(1) = a sin ( omega t + (pi)/(3)) and y_(2) = a sin omega t` is :A. aB. `sqrt(2)_(a)`C. `2a`D. `sqrt(3)_(a)`

Excess electrons are placed on a small lead sphere of mass `6.90 ` g so that its net charge is `-3.20 xx 10^(-9)C`. Find the number of excess electorns ( in terms of `xx 10^(10))` on the sphere.

The electric field strength depends only on the x, y, and z coordinates according to the law `E = (a(xhati+yhatj+zhatk))/(x^2+y^2+z^2)^3//2`, where ` a = 280 Nm^2C^(-1)` is a constant. If the potential difference between (3,2,6) and (0,3,4) is `x^2`. What is the value of x.

Two mutually perpendicular infinite wires along x-axis and y-axis carry charge densities `lambda_1 and lambda_2`. The electric line of force at P is along the line `y = x//(sqrt3)`, where P is also a point lying on the same line. Find `lambda_2//lambda_1`.

Who among the following won the 'BBC Sports Personality of the Year 2019' award ?1. Wayne Rooney2. Ben Stokes3. Ken Williamson4. Kylian Mbappé Lottin

If \( \log _{2}\left(a x^{2}+x+a\right) \geq 1 \forall x \in R \), then exhaustive set of values of ' \( a \) ' is:

If \( \log _{2}\left(a x^{2}+x+a\right) \geq 1 \forall x \in R \), then exhaustive set of values of ' \( a \) ' is:

Which of the following element shows only signle oxidation state in their compound except zero?A. HydrogenB. CarbonC. FluorineD. Oxygen

Consider the reaction: `P_(4)(s)+F_(2)(g)rarrPF_(3)(g)` How many gram of `F_(2)` are needed to produce 11.2 L of `PF_(3)` at NTP?A. 28.5gmB. 48gmC. 57gmD. 85.5gm

A projectile is thrown with a velocity `u_(0)` at an angle `theta` with the horizontal. The ratio of the rate of change of speed w.r.t. time, at highest point to that at the point of projection, isA. `g sin theta`B. `- g sin theta`C. zeroD. g

Find the components of vector `vec(a)=3hat(i)+4hat(j)` along the direction of vectors `hat(i)+hat(j)` & `hat(i)-hat(j)`

A square loop of side 2cm carrying current `I_(0)` is placed in x-y plane in a magnetic field `B= (4hat(i)+3hat(j))` T Find the unit vector along the axis about which it will start rotating. A. `(4hat(j)+3hat(i))/5`B. `(-4hat(j)-3hat(i))/5`C. `(-4hat(j)+3hat(i))/5`D. `(4hat(j)-3hat(i))/5`

A cell of internal resistance is connected across a resistor. A voltemeter having varible resistance `G` is used to meausre p.d. across resistor. The plot of voltmeter reading `V` against `G` is shown. What is value of external resitor `R` A. `5Omega`B. `4Omega`C. `3 Omega`D. `1 Omega`

Three charged particles are collinear and are in equilibrium, thenA. all the charged particles have the same polartiyB. the equilibrium is unstableC. all the charged particles cannot have the same polarityD. Both (b) and (c ) are correct

Suggest an experiment to produce a rainbow in your classroom.

Which among the above is / are true ?a : Force experienced by a charge moving in magnetic field is qvB. b : Magnetic field is weak at poles. c : Magnetic field lines are open loops. d : Magnetic field lines are open loops.

The power delivered by a battery of emf 10 V is 10 W, then what is the current delivered by the battery ?

A conductor is passing into the page. Guess the direction of the current through the conductor, if the magnetic field is formed as shown in the figure.

What is the bond angle (HOH) in a water molecule?

Refractive index of glass relative to water is 9/8 . What is the refractive index of water relative to glass ?

When the angle of incidence is greater than critical angle, the light ray is reflected into denser medium at interface".What is the value of angle of refraction, when angle of incidence is equal to critical angle ?

Among the above substances, for which substance the rate of rise in temperature is low if same quantity of heat is supplied ?SubstanceSpecific heat (cal /g –°CWater 1 Mercury0.033Copper0.095

Write modern periodic law.

What do you observe when phenolphthalein solution is added to NaOH solution?

The differentiating electron in one atom is '4p1'. (a) Write the set of 3 quantum numbers for it. (b) Write the full electronic configuration of the atom.

Which of the above material is a good conductor ? Why ?Material Resistivity (Ω- m)P1.68 × 10–8Q4.60 × 10–1 R10.0 × 1010

Predict the reasons for low melting point for covalent compounds when compared with ionic compounds.