45406 + Interview Questions in Physics in Class 12 Page 137 InterviewSolution

6801.	One way to keep the contents of a garage from becoming too cold on a night when a severe subfreezing temperature is forecast is to put a tub of water subfreezing temperature is forecast is to put a tub of water in the garage. If the mass of the water is 135 kg and its initial temperature is 20^(@)C, (a) how much energy must the water transfer to its surrounding in order to freeze competely and (b) what is the lowest possible temperature of the water and its surrounding until that happens?
Answer» ANSWER :(a) 56 MJ; (b) the lowest TEMPERATURE POSSIBLE is `0^(@)C`

Discussion

6802.	A radioactive nucleus (initial mass number A and atomic number Z) emits 3 alpha -particles and 2 positrons. The ratio of number of neutrons to that of protons in the final nucleus will be:
Answer» `(A-Z-4)/(Z-2)` `(A-Z-8)/(Z-4)` `(A-Z-4)/(Z-8)` `(A-Z-12)/(Z-4)` Solution :`""_(Z)^(A)X overset(-3alpha)to ""_(z-6)^(A-12)Y overset(-2_(1)E^(0))to ""_(z-8)^(A-12)Z` n=A-12-(Z-8)=A-12-Z+8 =A-Z-4 and p=Z-8 `n/p=(A-Z-4)/(Z-8)`

Discussion

6803.	Two wires A and B of same material having their lengths in the ratio 6:1 are connected in series. The p.d. across the wires are 3V and 2V respectively. If r_(B)//r_(A) and r_(B) are radii of A and B respectively, r_(B)//r_(A) is
Answer» `1//4` `1//2` 3 2 Answer :B

Discussion

6804.	A parallel plate capacitor is charged and then isolated. Now a dielectric slab is Introduced in it. Which of the following quantities will remain constant ?
Answer» Electric charge Q Potential difference V Capacitance C Energy U Solution :When dielectric SLAB is introduced in a parallel plate capacitor, its capacitance C = CK, where K = dielectric constant of a slab. But when C. is INCREASED accroding to `V = (Q)/(C) ` the potential V is DECREASED . Hence energy `U = (1)/(2)C^(1)V^(2)` also changes so charge Q remains constant.

Discussion

6805.	Energy released during the fission of one Uranium-235 nucleus is 200MeV. Energy released by the fission of 500gm of U-235 nuclei will be about
Answer» `3.5xx10^20` MEV `6.6xx10^24` MeV `2.8xx10^26` MeV `1.6xx10^31` MeV Answer :C

Discussion

6806.	In precious question the switch is kept closed for a long time and then assume it is opened at t = 0. Write the expression of charge on the capacitor as a function of time.
Answer» `q = 2CV E^(- t//3RC)` `q = CV e^(- t//3RC)` `q = CV e^(- t//2RC)` `q = CV e^(- 2t//3RC)` Solution :After the CAPACITOR is FULLY CHARGED then the amount of charge with it is Q=CV and it will be initial charge on capacitor when the switch is opened. When it is opened then the upper loop makes a discharging circuit and its time constant becomes 3RC. Using the expression of charge for discharging `q= q_(0) e^(-t//tau)` we can write the following expression. `q= CVe^(-t//3RC)` Hence OPTION (b) is correct

Discussion

6807.	A cyclist rides round a curved path of radius 10m at a speed 18 kmph. If the cycle and the rider together have a mass of 100 kg, the firctional force the ground exerts on the wheel is (g = 10 ms^(2))
Answer» 250 N 400 N 500 N 600 N Answer :A

Discussion

6808.	In case of superposition of waves (at x = 0). y_1 = 4 sin(1026 pi t) and y_2 = 2 sin(1014 pi t)
Answer» the frequency of RESULTING wave is 510 Hz the amplitude of resulting wave varies of frequency 3 Hz the frequency of beats is 6 Hz the RATIO of MAXIMUM to MINIMUM intensity is 9 Answer :A::B::C::D

Discussion

6809.	In thefollowing velocity time graph of a body the distance travelled by the body and its displacement during 5 second in meter will be : -
Answer» 75,75 70,30 `110,110` `110,40` ANSWER :B

Discussion

6810.	Which of the following transitions gives photon of maximum energy
Answer» n=1 to n=2 n=2 to n=1 n=2 to n=6 n=6 to n=2 ANSWER :B

Discussion

6811.	A ray of light in air is incident on a glass slab at an angle of incidence of 60^@ . When it travels through glass, it is deviated through 15^@ . What is the refractive index of the material of the glass slab?
Answer» 1.275 1.225 1.8 1.5 Answer :B

Discussion

6812.	For the damped oscillator shown in previous figure, k= 180 Nm^(-1) and the damping constant b is 40 gs^(-1) .Period of oscillation is given as 0.3 s, find the mass of the block . (Assume b is much less than sqrt(km)). Hint :T = 2pi sqrt((m)/(k))
Answer» SOLUTION :`T = 2pi sqrt((m)/(K))` `= m = ( T^(2)k)/(4pi^(2))= ( 0.3 xx 0.3 xx 180)/( 4 xx ( 3.14 )^(2)) = 0.4 kg `

Discussion

6813.	Two monochromatic light waves of equal intensities produce an interference pattern. At a point in the pattern, the phase difference between the interfering waves is pi//2 rad. Express the intensity at this point as a fraction of the maximum intensity in the pattern.
Answer» Solution :Data: `I_(1) = I_(2) = I_(0),PHI = pi//2` rad The resultant intensity at the point in the pattern is `I= I_(1) + I_(2) + 2sqrt(I_(1)I_(2)) cosphi` `=I_(0) + I_(0) = 2sqrt(I_(0)I_(0))cosphi` `= 2I_(0)(1+1) = 4I_(0)`...................(i) Also, `1+ cosphi = 2 cos^(2) phi/2`................(2) Also, `1+cosphi = 2 cos^(2) phi/2`.........(3) From Eqs. (1) and (3), `I= 2I_(0)(2cos^(2)phi/2)`[From Eq. (2)] `I=2I_(0) ( 2cos^(2)phi/2)` `=I_("MAX")(cospi/4)^(2) = I_("max")(1/sqrt(2))^(2)` `THEREFORE I= 1/2I_("max")`

Discussion

6814.	The zeros of the polynomial x^2+16x-2 are
Answer» `-3,4` `-3/2,4/3` `-4/3,3/2` NONE of these Answer :D

Discussion

6815.	(a)Using Bohr's postulates, derive the expression for the total energy of the electron revolving in nth orbit of hydrogen atom. (b) Find the wavelength of the H_(alpha) line. Given the value of Rydberg constant is 1.1 xx 10^(7) m^(-1).
Answer» Solution :(a) See SHORT ANSWER Question NUMBER 32. (B) See Short Answer Question Number 17.

Discussion

6816.	what is greater? The attraction of earth for an apple or attraction of the apple on the earth?
Answer» Solution :The earth is a stable-orbit and the GRAVITATIONAL force of ATTRACTION of the SUN is PERPENDICULAR to it’s VELOCITY.

Discussion

6817.	What is the ground-state energy of (a) an electron and (b) a proton if each is trapped in a one-dimensional infinite potential well that is 300 pm wide?
Answer» SOLUTION :(a) `1.51xx10^(-18)J`, (B) `8.225xx10^(-22)J`

Discussion

6818.	In the circuit, various resistance and five batteries are connected as shown in the figure. If point O is earthed,
Answer» the current in the battery marked as A is`1//2 A` . the potential of point X marked in circuit is 15 V. the current through the battery marked as C is 2A. Solution :a.,c.,d. From circuit diagram it is clear `I_1 = (15-5)/6 = 2A, I_2 = (15-10)/2 = 2.5A` Taking BRANCH xM `15 + 2I_3 - 15 = 10 or I_3 = 5A` Taking branch N O `5+5-5I_4 = 0 or I_4 = 2A` In junction `x: I_3 = I_1 + I_2 + I_A` `5 = 2+ 2.5 = I_A or I_A = 1/2 A` In junctionB: ` I_1 + I_A = I_4 + I_B` or `2.0 + 0.5 = 2 + I_(B) or I_(B) = 1/2 A`.

Discussion

6819.	Young's double slit experiment is made in a liquid . The 10th bright fringe in liquid lies where 6th dark fringe lies in vacuum. The refractive index of the liquid is approximately .
Answer» Solution :FRINGE width `beta = (lambda D)/(d)`. When the apparatus is IMMERSED in a LIQUID,`lambda ` and hence `beta `is REDUCED`mu`(refractive index) TIMES. `10 beta . = (5.5) beta or 10 lambda. ((D)/(d)) =(5.5) (lambda D)/(d)` or`(lambda)/(lambda.) = (10)/(5.5) = mu or mu = 1.8`

Discussion

6820.	When an unpolarised light of intensity I_0 is incident on a polarising sheet, the intensity of the light which does not get transmitted is
Answer» zero `I_(0)` `(1)/(2)I_(0)` `(1)/(4)I_(0)` Solution :The intensity of transmitted light through the POLARISING SHEET `I=(I_(0))/(2)`. `therefore` Intensity of light which does not get transmitted `=I_(0)-I=I_(0)-(I_(0))/(2)=(I_(0))/(2)`.

Discussion

6821.	All zeros to the right of the last nonzero digit after the decimal point are significant. B) If the number is less than one, all the zeros to the right of the decimal point but to the left of the first nonzero digit are not significant.
Answer» Only A is CORRECT A, B are correct Only B is correct A, B are WRONG ANSWER :B

Discussion

6822.	Unpolarised light of intensity 32 Wm^(-2) passes through three polarisers such that the transmission axis of the last polariser is crossed with first. If the intensity of the emerging light is 3Wm^(-2), the angle between the axes of the first two polarisers is
Answer» `45^(@)` `60^(@)` `30^(@)` Zero Answer :C

Discussion

6823.	The displacement in Newton law corresponds to …... is electrical quantity.
Answer» electromagnetic force current electric charge the RATE of change of electric charge Solution :Here `(d^2y)/(dt^2)` term corresponds to the differential EQUATION for FORCED harmonic motion is `(d^2Q)/(dt^2)` ,so corresponds PHYSICAL equation is Q.

Discussion

6824.	In a zener diode, the reverse bias voltage is 3V and width of the depletion region is 300 Å, the electric field intensity will be ……., (V)/(cm).
Answer» `10^(4)` `10^(8)` `10^(6)` `10^(-2)` Solution :`10^(6)` `E=(V)/(d)` `=(3)/(3XX10^(-8))=10^(+8)(V)/(m) therefore E=10^(6)(V)/(cm)`

Discussion

6825.	The Churun river is a tributary of
Answer» Ganga Thames Nile Caroni Answer :D

Discussion

6826.	Centre of mass of a hollow or solid sphere lies at the _____.
Answer» SOLUTION :[CENTRE]

Discussion

6827.	A motor vehicle travelled the first third of a distance s at a speed of V_(1)=10 kmph,the second third at a speed of V_(2)=20 kmph and the last third at a sped of V_(3)=60 kmph. Determine the mean speed of the vehicle over the entire distance s.
Answer» 15 kmph 12kmph 10 kmph 18 kmph Answer :D

Discussion

6828.	In a meter bridge 30 Omegaresistance is connected in the left gap and a pair of resistance 20 Omegaand Q in (Ohm) are in right gap and they are connected in series, then the balanceing length is 50 cm. When they were connected in parallel the balanceing length will be
Answer» 20 CM 40 cm 60 cm 81.81 cm Answer :D

Discussion

6829.	What are the two most important properties of charge ?
Answer» SOLUTION :CHARGE in quantized and CONSERVED.

Discussion

6830.	The maximum number of possible interference maxima for slit separation equal to twice the wavelength in Young's double slit experiment
Answer» infinite five three zero Answer :C

Discussion

6831.	What happens to the pressure, P, of an ideal gas if the temperature is increased by a factor of 2 and the volume is increased by a factor of 8 ?
Answer» P DECREASES by a factor of 16 P decreases by a factor of 4 P decreases by a factor of 2 P increases by a factor of 4 Solution :USE the ideal gas LAW, `P'=(nRT')/(V')=(NR(2T))/(8V)=(1)/(4)(nRT)/(V)=(1)/(4)P`

Discussion

6832.	What we call the ratioof the angular dispersion between two colors to the deviation caused by the mean colors ?
Answer» SOLUTION :DISPERSIVE POWER

Discussion

6833.	(a)Derive the expression for the torque on a rectangular current carrying loop suspended in a uniform magnetic field. (b)A proton and a deuteron having equal momenta enter in a a region of a uniform magnetic field at right angle to the direction of a the field.Depict their trajectories in the field. OR (a)A small compass needle of magnetic moment m is free to turn about an axis perpendicular to the direction of unifrom magnetic field B.The moment of inertia of the needle about the axis is I.The needle is slightly disturbed form its stable position and then released.Prove that it executes simple harmonic motion.Hence deduce the expression for its time period. (b) A compass needle, free to turn in a vertical plane orients inself with its axis vertical at a certain place on the earth.Find out the values of (i)horizontal component of earth's magnetic field and (ii) angle of dip at the place.
Answer» Solution :Where `theta=` angle between velocity of particle and magnetic FIELD `=90^(@)` So,Lorentz force, `F=BqV` Thus the particles will move in circular path. `Bqupsilon=(mV^(2))/r rArrr=(mV)/(Bq)` Let `m_(p)=` mass of proton `m_(d)=` mass of deuteron, `V_(p)=` velocity of proton and `V_(d)=`velocity of deuteron.The CHARGE of proton and deuteron are equal. Given that `m_(p)V_(p)=m_(d)V_(d)` `r_(p)=(m_(p)upsilon_(p))/(Bq)`...(i) `r_(d)=(m_(d)upsilon_(d))/(Bq)`...(ii) As (i) and (ii) are equal so `r_(p)=r_(d)=r` Thus, the trajectory of both the particles will be same. OR (b)(i)As Horizontal component of earth's magnetic field `B_(H)=Bcos delta` Putting `=delta=90^(@) therefore B_(H)=0` (ii)For a compass NEEDLE align vertical at a certain place, angle of DIP , `delta=90^(@)`

Discussion

6834.	A place where the vertical component of Earth's magnetic field is zero has the angle of dip equal to .........
Answer» `0^@` `45^@` `60^@` `90^@` Solution :In `TAN PHI = (B_v)/( B_h) , B_v = 0` `THEREFORE tan phi = (0)/(B_h)` `therefore tan phi = 0` `therefore phi = tan^(-1) (0)` `therefore phi=0^@`

Discussion

6835.	Which of the following is a ratinal number?
Answer» `PI` `0.853853853....` `0.101001000` `SQRT 7` ANSWER :B

Discussion

6836.	For L-R circuit, the time constant is equal to
Answer» twice the RATIO of the ENERGY strored in the magnetic FIELD to the rate of dissipation of energy in the resistance the ratio of the energy STORED in the magnetic field to the rate of dissipation of energy in the resistance. half of the ratio of the energy stored in the magnetic field to the rate of dissipation of energy in the resistance square of the ratio of the energy stored in the magnetic field to the rate of dissipation of energy in the resistance Solution :`tau=(2xx1/2LI^(2))/(I^(2)R)=L/R`

Discussion

6837.	Two parallel plate capacitors X and Y have the same area of plates and same separation between them. X has air between the plates while Y contains a dielectric medium of εr= 4.(i) Calculate capacitance of each capacitor if equivalent capacitance of the combination is 4 μF.(ii) Calculate the potential difference between the plates ofX and Y.(iii) Estimate the ratio of electrostaticenergy stored in X and Y.
Answer» SOLUTION :i. LET V be the p.d. across X. Then p.d. across Y will be `V/5`. `therefore V+V/5="12 VOLT "rArr (6V)/(5)="12 volt or V=10volt"` p.d. across X=10 volt p.d. across `Y=(10)/(5)="2 volt"` ii. `("Energy stored in X")/("Energy stored in Y")=(1/2 C(10)^(2))/(1/2 5C(2)^(2))=(100)/(20) 5:1 [therefore E=1/2 CV^(2)]`

Discussion

6838.	Find the time of relaxation between collsion and free path of electrons in copper at room temperature. Given resistivity of copper=1.7xx10^(-8) Omegam, number density of electrons in copper =8.5xx10^(28) m^(-3), charge on electron=1.6xx10^(-19) C, mass of electron =9.1xx10^(-3) kg and drift velocity of free electrons=1.6xx10^(-4) ms^(-1)
Answer» ANSWER :`2.5xx10^(-14)s, 4.0xx10^(-8) m`

Discussion

6839.	A stone is dropped from a tower of height 200 m and at the same time another stone is projected vertically up at 50 m/s. The height at which they meet ? [g=10 "m/s"^2]
Answer» 5 m 100 m 120 m 125 m Answer :C

Discussion

6840.	In an AC circuit, the reactance is equal to the resistance. What is the power Factor of the circuit ?
Answer» 44198 `1/sqrt2` 1 Zero Answer :B

Discussion

6841.	If binding energy per nucleon in " "_(3)^(7)Li and " "_(4)^(2)He nuclei be 5.60 MeV and 7.06 MeV respectively, then energy released in nuclear reaction " "_(3)^(7)Li+" "_(1)^(1)Hto2" "_(2)^(4)He is
Answer» 19.6 MeV 2.4 MeV 8.4 MeV 17.3 MeV Answer :D

Discussion

6842.	9765 /14.39 = 678.59625. This quotient on rounding off to two significant figures is
Answer» 680 70 `678.6 ` 679 Answer :A

Discussion

6843.	A parallel beam falls on solid glass sphere of radius R and refractive index mu. What is the distance of final image after refractioin from two surfaces of sphere? What is the condition for the image to be real?
Answer» `(R(mu-2))/(2(mu-1))` from 2ND SURFACE , `mugt2` `(R(2-mu))/(2(mu-1))` from 2nd surface `mult2` `(R(mu-1))/((2-mu))` from 2nd surface `mult2` `R/2((mu+2)/(mu-1))` from 2nd surface `mult2` for any value of `mu` ANSWER :C

Discussion

6844.	Whichamongthe curvescannot possibly representelectrostatic fieldlines ?
Answer» SOLUTION :`9.81 xx10^(-4)` MM

Discussion

6845.	The time constant of a certain inductive coil was found to be 2.5 ms. With a resistance of 80Omegaadded in series, a new time constant of 0.5 ms was obtained. Find the inductance and resistance of the coil.
Answer» Solution :TIME constant , `tau_L = L/R ` For the first case , `L/R = 2.5 xxx 10^(-3) sec to (1)` For th second case , `(L)/(R+80) = 0.5 xx 10^(-3) to (2)` Divide (1) by (2) `(R+80)/( R)= (2.5)/(0.5) = 5` SOLVING we get : `R = 20 Omega ` now ,` L/R= 2.5 xx 10^(-3)` ` L = 2.5 xx 10^(-3) xx 20 = 50mH`

Discussion

6846.	(A): Primary cells can be recharged, but secondary cells can not be recharged. (R): Chemical reactions involved in secondary cells are irreversible and in primary cells are reversible.
Answer» Both 'A' and 'R' are true and 'R' is the CORRECT EXPLANATION of 'A' Both 'A' and 'R' are true and 'R' is not the correct explanation of 'A' 'A' is true and 'R' is FALSE 'A' is false and 'R' is false ANSWER :D

Discussion

6847.	The electrohic iransmission of a document to a distance place by using telephone lines is known as:
Answer» E-mail Fax Wireless Moderm Answer :B

Discussion

6848.	In the process of nuclear fission of 1 gram uranium, the mass lost is 0.92 milligram. The efficiency of power house run by it is 10%. To obtain 400 megawatt power from the power house, how much uranium will be required per hour? (c=3xx10^8 "ms"^(-1))
Answer» Solution :Power to be obtained from power house = 400 mega watt `therefore` Energy obtained per HOUR = 400 mega watt x 1hour= (`400xx10^6` watt) x 3600 second = `1.44xx10^10` joule Here only 10% of input is utilized. In order to obtain `144 XX 10^10`joule of useful energy, the output energy from the power house `(10E)/100=144xx10^10` J, E=`1.44xx10^11`joule Let, this energy is obtained from a mass-loss of `Deltam` kg. Then `(Deltam)c^2=144xx10^11` joule `Deltam=(144xx10^11)/(3xx10^8)^2=16xx10^(-5)` kg = 0.16 gm Since 0.92 milli gram (= `0.92xx10^(-3)` gm)mass is LOST in 1 gm URANIUM , hence for a mass loss of 0.16 gm, the uranium required is `=(1xx0.16)/(0.92xx10^(-3))` = 174 gm Thus to run the power house, 174 gm uranium is required per hour.

Discussion

6849.	(A) For the scattering of a.-particles at a large angles. only the nucleus of the atom is responsible. (R) : Nucleus is very heavy in comparison to electrons.
Answer» Both 'A' and 'R' are TRUE and 'R' is the CORRECT explanation of 'A'. Both 'A' and 'R' are true and 'R' is not the correct explanation of 'A' 'A' is true and 'R' is FALSE 'A' is false and 'R' is true ANSWER :A

Discussion

6850.	What is the height of the highest waterfall?
Answer» 980m 920m 950m 960m Answer :D

Discussion

Explore topic-wise InterviewSolutions in .

A radioactive nucleus (initial mass number A and atomic number Z) emits 3 alpha -particles and 2 positrons. The ratio of number of neutrons to that of protons in the final nucleus will be:

Two wires A and B of same material having their lengths in the ratio 6:1 are connected in series. The p.d. across the wires are 3V and 2V respectively. If r_(B)//r_(A) and r_(B) are radii of A and B respectively, r_(B)//r_(A) is

A parallel plate capacitor is charged and then isolated. Now a dielectric slab is Introduced in it. Which of the following quantities will remain constant ?

Energy released during the fission of one Uranium-235 nucleus is 200MeV. Energy released by the fission of 500gm of U-235 nuclei will be about

In precious question the switch is kept closed for a long time and then assume it is opened at t = 0. Write the expression of charge on the capacitor as a function of time.

A cyclist rides round a curved path of radius 10m at a speed 18 kmph. If the cycle and the rider together have a mass of 100 kg, the firctional force the ground exerts on the wheel is (g = 10 ms^(2))

In case of superposition of waves (at x = 0). y_1 = 4 sin(1026 pi t) and y_2 = 2 sin(1014 pi t)

In thefollowing velocity time graph of a body the distance travelled by the body and its displacement during 5 second in meter will be : -

Which of the following transitions gives photon of maximum energy

A ray of light in air is incident on a glass slab at an angle of incidence of 60^@ . When it travels through glass, it is deviated through 15^@ . What is the refractive index of the material of the glass slab?

For the damped oscillator shown in previous figure, k= 180 Nm^(-1) and the damping constant b is 40 gs^(-1) .Period of oscillation is given as 0.3 s, find the mass of the block . (Assume b is much less than sqrt(km)). Hint :T = 2pi sqrt((m)/(k))

Two monochromatic light waves of equal intensities produce an interference pattern. At a point in the pattern, the phase difference between the interfering waves is pi//2 rad. Express the intensity at this point as a fraction of the maximum intensity in the pattern.

The zeros of the polynomial x^2+16x-2 are

(a)Using Bohr's postulates, derive the expression for the total energy of the electron revolving in nth orbit of hydrogen atom. (b) Find the wavelength of the H_(alpha) line. Given the value of Rydberg constant is 1.1 xx 10^(7) m^(-1).

what is greater? The attraction of earth for an apple or attraction of the apple on the earth?

What is the ground-state energy of (a) an electron and (b) a proton if each is trapped in a one-dimensional infinite potential well that is 300 pm wide?

In the circuit, various resistance and five batteries are connected as shown in the figure. If point O is earthed,

Young's double slit experiment is made in a liquid . The 10th bright fringe in liquid lies where 6th dark fringe lies in vacuum. The refractive index of the liquid is approximately .

When an unpolarised light of intensity I_0 is incident on a polarising sheet, the intensity of the light which does not get transmitted is

All zeros to the right of the last nonzero digit after the decimal point are significant. B) If the number is less than one, all the zeros to the right of the decimal point but to the left of the first nonzero digit are not significant.

Unpolarised light of intensity 32 Wm^(-2) passes through three polarisers such that the transmission axis of the last polariser is crossed with first. If the intensity of the emerging light is 3Wm^(-2), the angle between the axes of the first two polarisers is

The displacement in Newton law corresponds to …... is electrical quantity.

In a zener diode, the reverse bias voltage is 3V and width of the depletion region is 300 Å, the electric field intensity will be ……., (V)/(cm).

The Churun river is a tributary of

Centre of mass of a hollow or solid sphere lies at the _____.

A motor vehicle travelled the first third of a distance s at a speed of V_(1)=10 kmph,the second third at a speed of V_(2)=20 kmph and the last third at a sped of V_(3)=60 kmph. Determine the mean speed of the vehicle over the entire distance s.

In a meter bridge 30 Omegaresistance is connected in the left gap and a pair of resistance 20 Omegaand Q in (Ohm) are in right gap and they are connected in series, then the balanceing length is 50 cm. When they were connected in parallel the balanceing length will be

What are the two most important properties of charge ?

The maximum number of possible interference maxima for slit separation equal to twice the wavelength in Young's double slit experiment

What happens to the pressure, P, of an ideal gas if the temperature is increased by a factor of 2 and the volume is increased by a factor of 8 ?

What we call the ratioof the angular dispersion between two colors to the deviation caused by the mean colors ?

A place where the vertical component of Earth's magnetic field is zero has the angle of dip equal to .........

Which of the following is a ratinal number?

For L-R circuit, the time constant is equal to

A stone is dropped from a tower of height 200 m and at the same time another stone is projected vertically up at 50 m/s. The height at which they meet ? [g=10 "m/s"^2]

In an AC circuit, the reactance is equal to the resistance. What is the power Factor of the circuit ?

If binding energy per nucleon in " "_(3)^(7)Li and " "_(4)^(2)He nuclei be 5.60 MeV and 7.06 MeV respectively, then energy released in nuclear reaction " "_(3)^(7)Li+" "_(1)^(1)Hto2" "_(2)^(4)He is

9765 /14.39 = 678.59625. This quotient on rounding off to two significant figures is

A parallel beam falls on solid glass sphere of radius R and refractive index mu. What is the distance of final image after refractioin from two surfaces of sphere? What is the condition for the image to be real?

Whichamongthe curvescannot possibly representelectrostatic fieldlines ?

The time constant of a certain inductive coil was found to be 2.5 ms. With a resistance of 80Omegaadded in series, a new time constant of 0.5 ms was obtained. Find the inductance and resistance of the coil.

(A): Primary cells can be recharged, but secondary cells can not be recharged. (R): Chemical reactions involved in secondary cells are irreversible and in primary cells are reversible.

The electrohic iransmission of a document to a distance place by using telephone lines is known as:

In the process of nuclear fission of 1 gram uranium, the mass lost is 0.92 milligram. The efficiency of power house run by it is 10%. To obtain 400 megawatt power from the power house, how much uranium will be required per hour? (c=3xx10^8 "ms"^(-1))

(A) For the scattering of a.-particles at a large angles. only the nucleus of the atom is responsible. (R) : Nucleus is very heavy in comparison to electrons.

What is the height of the highest waterfall?