50278 + Interview Questions in Physics Page 98 InterviewSolution

4851.	Calculate the speed of sound in oxygen from the following data. The mass of 22.4 litre of oxygen at STP (T = 273 K and P = 1.0× 105 N m−2) is 32g, the molar heat capacity of oxygen at constant volume is CV = 2.5 R and that at constant pressure is Cp = 3.5 R.
Answer» Calculate the speed of sound in oxygen from the following data. The mass of 22.4 litre of oxygen at STP $(T = 273 K a n d P = 1.0 \times 10^{5} N m^{- 2})$ is 32g, the molar heat capacity of oxygen at constant volume is $C_{V}$ = 2.5 R and that at constant pressure is Cp = 3.5 R.

Discussion

4852.	44.If separate samples of argon methane nitrogen and carvon dioxide all at the same intial temperature and pressyre and expanded adibatically reversiy to double thier original volume then which of the following gases have high temperature as final temperature
Answer» 44.If separate samples of argon methane nitrogen and carvon dioxide all at the same intial temperature and pressyre and expanded adibatically reversiy to double thier original volume then which of the following gases have high temperature as final temperature

Discussion

4853.	how to take VERNIER SCALE READING and find length of object ?
Answer» how to take VERNIER SCALE READING and find length of object ?

Discussion

4854.	Find the magnetic field at a point which is at 2 m on perpendicular bisector of finite current carrying wire of length 6 m. If the current of 10A is flowing as shown in the figure, then which of the following options is the correct magnetic field at that point.
Answer» Find the magnetic field at a point which is at $2 m$ on perpendicular bisector of finite current carrying wire of length $6 m$ . If the current of $10 A$ is flowing as shown in the figure, then which of the following options is the correct magnetic field at that point.

Discussion

4855.	A disc of mass m0 rotates freely about a fixed horizontal axis passing through its center. A thin cotton pad is fixed to its rim, which can absorb water. The mass of water dripping onto the pad per unit time is μ. After what time will the angular velocity of the disc get reduced to half its initial value?
Answer» A disc of mass $m_{0}$ rotates freely about a fixed horizontal axis passing through its center. A thin cotton pad is fixed to its rim, which can absorb water. The mass of water dripping onto the pad per unit time is $μ$ . After what time will the angular velocity of the disc get reduced to half its initial value?

4855.

A disc of mass m0 rotates freely about a fixed horizontal axis passing through its center. A thin cotton pad is fixed to its rim, which can absorb water. The mass of water dripping onto the pad per unit time is μ. After what time will the angular velocity of the disc get reduced to half its initial value?

Answer»

A disc of mass $m_{0}$ rotates freely about a fixed horizontal axis passing through its center. A thin cotton pad is fixed to its rim, which can absorb water. The mass of water dripping onto the pad per unit time is $μ$ . After what time will the angular velocity of the disc get reduced to half its initial value?

Discussion

4856.	34.Reading shown by the hot wire voltmeter used in the circuit here is____
Answer» 34.Reading shown by the hot wire voltmeter used in the circuit here is____

Discussion

4857.	Eight identical resistors each of resistance r are connected along edges of a pyramid having square base ABCD as shown in figure.The equivalent resistance between A and O is
Answer» Eight identical resistors each of resistance $r$ are connected along edges of a pyramid having square base $A B C D$ as shown in figure.The equivalent resistance between $A$ and $O$ is

Discussion

4858.	A closed organ pipe has a length l. The air in it is vibrating in third overtone with maximum displacement amplitude of a. The displacement amplitude at distance l/7 from the closed end of the pipe will be
Answer» A closed organ pipe has a length $l$ . The air in it is vibrating in third overtone with maximum displacement amplitude of $a$ . The displacement amplitude at distance $l / 7$ from the closed end of the pipe will be

Discussion

4859.	A wave is represented by y=0.1sin(100πt−kx), where y,t,x are in SI units. If wave velocity is 100 m/s, its wave number is
Answer» A wave is represented by $y = 0.1 sin (100 π t - k x),$ where $y, t, x$ are in SI units. If wave velocity is $100 m/s,$ its wave number is

Discussion

4860.	A bullet moving with a velocity of 100 m/s can just penetrate two planks of equal thickness. The number of such planks penetrated by the same bullet, when the velocity is doubled, will be
Answer» A bullet moving with a velocity of 100 m/s can just penetrate two planks of equal thickness. The number of such planks penetrated by the same bullet, when the velocity is doubled, will be

Discussion

4861.	For the two parallel rays (AB and DE) of same wavelength λ, BD is the wavefront. The phase difference of these two rays at point D is
Answer» For the two parallel rays $(AB and DE)$ of same wavelength $λ$ , $BD$ is the wavefront. The phase difference of these two rays at point $D$ is

Discussion

4862.	Helium in a piston/cylinder at 27∘C, 100 kPa is brought to 400 K in a reversible polytropic process with exponent n=1.25. Helium can be assumed to be an ideal gas with constant specific heat capacity. Find the work done per unit mass of gas. Assume R for helium =2.07 kJ/kg K
Answer» Helium in a piston/cylinder at $27^{\circ} C,$ $100 kPa$ is brought to $400 K$ in a reversible polytropic process with exponent $n = 1.25$ . Helium can be assumed to be an ideal gas with constant specific heat capacity. Find the work done per unit mass of gas. Assume $R$ for helium $= 2.07 kJ/kg K$

Discussion

4863.	A car moving along a straight highway with speed of 126 km h¯¹ is brought to a stop within a distance of 200 m. What is the retardation of the car (assumed uniform), and how long does it take for the car to stop ?
Answer» A car moving along a straight highway with speed of 126 km h¯¹ is brought to a stop within a distance of 200 m. What is the retardation of the car (assumed uniform), and how long does it take for the car to stop ?

Discussion

4864.	39. If m1=10kg;m2=4kg;m3:2kg,the acceleration of the system is ?
Answer» 39. If m1=10kg;m2=4kg;m3:2kg,the acceleration of the system is ?

Discussion

4865.	A convex mirror has the largest field of view among all the mirrors. This property is used in
Answer» A convex mirror has the largest field of view among all the mirrors. This property is used in

Discussion

4866.	A ‘thermacole’ icebox is a cheap and an efficient method for storing small quantities of cooked food in summer in particular. A cubical icebox of side 30 cm has a thickness of 5.0 cm. If 4.0 kg of ice is put in the box, estimate the amount of ice remaining after 6 h. The outside temperature is 45 °C, and co-efficient of thermal conductivity of thermacole is 0.0 s¯¹m–1 K¯¹. [Heat of fusion of water = 335 × 103 J kg¯¹]
Answer» A ‘thermacole’ icebox is a cheap and an efficient method for storing small quantities of cooked food in summer in particular. A cubical icebox of side 30 cm has a thickness of 5.0 cm. If 4.0 kg of ice is put in the box, estimate the amount of ice remaining after 6 h. The outside temperature is 45 °C, and co-efficient of thermal conductivity of thermacole is 0.0 s¯¹m–1 K¯¹. [Heat of fusion of water = 335 × 103 J kg¯¹]

Discussion

4867.	A point object having charge q and mass m kept on the top of a frictionless and insulated hemisphere. When a horizontal electric field is applied, the object starts sliding down and loses contact from the surface at an angle θ=sin−135 from the vertical. The ratio of force of gravity and the force due to interaction with the field acting on this object is
Answer» A point object having charge $q$ and mass $m$ kept on the top of a frictionless and insulated hemisphere. When a horizontal electric field is applied, the object starts sliding down and loses contact from the surface at an angle $θ = s i n^{- 1} \frac{3}{5}$ from the vertical. The ratio of force of gravity and the force due to interaction with the field acting on this object is

Discussion

4868.	Light of wavelength 200 nm shines on an aluminium, 4.20 eV is required to eject an electron. What is the kinetic energy of the fastest ejected electrons in eV? (take h=6.6×10−34 Js)
Answer» Light of wavelength 200 nm shines on an aluminium, $4.20 eV$ is required to eject an electron. What is the kinetic energy of the fastest ejected electrons in eV? (take $h = 6.6 \times 10^{- 34} J s$ )

Discussion

4869.	28. In a Bohrs model of an atom, when an electron jumps from n = 1 to n = 3, how much energy will be emitted or absorbed?
Answer» 28. In a Bohrs model of an atom, when an electron jumps from n = 1 to n = 3, how much energy will be emitted or absorbed?

Discussion

4870.	Area bounded by y=xsin x and x- axis between x=0 and x=2π, is
Answer» Area bounded by $y = x s i n x$ and $x$ - axis between $x = 0$ and $x = 2 π$ , is

Discussion

4871.	A particle is projected upward from the surface of earth (radius = R) with a speed equal to the orbital speed of a satellite near the earth's surface. The height to which it would rise is
Answer» A particle is projected upward from the surface of earth (radius = R) with a speed equal to the orbital speed of a satellite near the earth's surface. The height to which it would rise is

Discussion

4872.	A electron gets emitted from the surface of a tungsten filament whose work function is 43.6ev. if the emitted electron escapes with a velocity of 2\ast10^6 m/s . calculate energy of incident radiation
Answer» A electron gets emitted from the surface of a tungsten filament whose work function is 43.6ev. if the emitted electron escapes with a velocity of 2\ast10^6 m/s . calculate energy of incident radiation

Discussion

4873.	In a medium in which a transverse progressive wave is travelling, the phase difference between two points with a separation of 1.25 cm is (π/4). If the frequency of wave is 1000 Hz, its velocity in m/s will be
Answer» In a medium in which a transverse progressive wave is travelling, the phase difference between two points with a separation of $1.25 cm$ is $(π / 4)$ . If the frequency of wave is $1000 Hz$ , its velocity in $m/s$ will be

Discussion

4874.	A thin insulating rod of mass m and length L is hinged at its upper end (O) so that it can freely rotate in vertical plane. The linear charge density on the rod varies with distance (y) measured from upper end asλ=⎧⎪⎪⎨⎪⎪⎩ay2for 0≤y≤L2−bynfor L2≤y≤L Where a and b both are positive constants. when a horizontal electric field E is switched on the rod is found to remain stationary. Find the value of ab. (Give integer value)
Answer» A thin insulating rod of mass $m$ and length $L$ is hinged at its upper end $(O)$ so that it can freely rotate in vertical plane. The linear charge density on the rod varies with distance $(y)$ measured from upper end as $λ = ⎧ ⎪⎪ ⎨ ⎪⎪ ⎩ \begin{matrix} a y^{2} & for 0 \leq y \leq \frac{L}{2} - b y^{n} & for \frac{L}{2} \leq y \leq L \end{matrix}$ Where $a$ and $b$ both are positive constants. when a horizontal electric field $E$ is switched on the rod is found to remain stationary. Find the value of $\frac{a}{b}$ . (Give integer value)

Discussion

4875.	Two particles having masses m1 and m2are situated in a plane perpendicular to line AB at a distance ofr1and r2 respectively as shown. Find the moment of intertia about axis passing through centre of mass and perpendicular to line joining m1 and m2
Answer» Two particles having masses $m_{1}$ and $m_{2}$ are situated in a plane perpendicular to line AB at a distance of $r_{1}$ and $r_{2}$ respectively as shown. Find the moment of intertia about axis passing through centre of mass and perpendicular to line joining $m_{1}$ and $m_{2}$

4875.

Two particles having masses m1 and m2are situated in a plane perpendicular to line AB at a distance ofr1and r2 respectively as shown. Find the moment of intertia about axis passing through centre of mass and perpendicular to line joining m1 and m2

Answer»

Two particles having masses $m_{1}$ and $m_{2}$ are situated in a plane perpendicular to line AB at a distance of $r_{1}$ and $r_{2}$ respectively as shown.

Find the moment of intertia about axis passing through centre of mass and perpendicular to line joining $m_{1}$ and $m_{2}$

Discussion

4876.	The position of a particle travelling along x - axis is given by xt = t3 - 9 t2 + 6t where xt is in m and t is in second . Then 1) the particle does not come to rest at all. 2) the particle comes to rest firstly at (3 - √7 ) s and then at (3 + √7) s 3) the speed of the particle at t= 2s is 18 ms−1 4) the acceleration of the particle at t= 2s is 6 ms−2
Answer» The position of a particle travelling along x - axis is given by $x_{t}$ = $t^{3}$ - 9 $t^{2}$ + 6t where $x_{t}$ is in m and t is in second . Then 1) the particle does not come to rest at all. 2) the particle comes to rest firstly at (3 - $\sqrt{7}$ ) s and then at (3 + $\sqrt{7}$ ) s 3) the speed of the particle at t= 2s is 18 m $s^{- 1}$ 4) the acceleration of the particle at t= 2s is 6 m $s^{- 2}$

4876.

The position of a particle travelling along x - axis is given by xt = t3 - 9 t2 + 6t where xt is in m and t is in second . Then 1) the particle does not come to rest at all. 2) the particle comes to rest firstly at (3 - √7 ) s and then at (3 + √7) s 3) the speed of the particle at t= 2s is 18 ms−1 4) the acceleration of the particle at t= 2s is 6 ms−2

Answer»

The position of a particle travelling along x - axis is given by $x_{t}$ = $t^{3}$ - 9 $t^{2}$ + 6t where $x_{t}$ is in m and t is in second . Then

1) the particle does not come to rest at all.

2) the particle comes to rest firstly at (3 - $\sqrt{7}$ ) s and then at (3 + $\sqrt{7}$ ) s

3) the speed of the particle at t= 2s is 18 m $s^{- 1}$

4) the acceleration of the particle at t= 2s is 6 m $s^{- 2}$

Discussion

4877.	33.With what speed a ball would be projected upwards so that distance travelled in 5th and 6th would be equal A) 49 m/s B)98 m/s C)58 m/s. D)none of these
Answer» 33.With what speed a ball would be projected upwards so that distance travelled in 5th and 6th would be equal A) 49 m/s B)98 m/s C)58 m/s. D)none of these

Discussion

4878.	1. Electrochemical series
Answer» 1. Electrochemical series

Discussion

4879.	What is the phase difference between I and E if E=E0sin(ωt) and I=I0cos(ωt+π3)?
Answer» What is the phase difference between $I$ and $E$ if $E = E_{0} sin (ω t)$ and $I = I_{0} cos (ω t + \frac{π}{3})$ ?

Discussion

4880.	A point charge q moves with velocity v along a straight line. Displacement current density at a point located at a distance r from charge and in the line of motion of the charge will be
Answer» A point charge q moves with velocity v along a straight line. Displacement current density at a point located at a distance r from charge and in the line of motion of the charge will be

Discussion

4881.	A player kicks a football at an angle of 45∘ with a velocity of 20 ms−1. A second player 60 m away along the direction of kick starts running to receive the ball at that instant. Find the speed with which second player should run to reach the ball before it hits the ground (g=10 ms−2)
Answer» A player kicks a football at an angle of $45^{\circ}$ with a velocity of $20 m s^{- 1}$ . A second player $60 m$ away along the direction of kick starts running to receive the ball at that instant. Find the speed with which second player should run to reach the ball before it hits the ground $(g = 10 m s^{- 2})$

Discussion

4882.	In a series LCR circuit the voltage across C,R and L are 10V each. If the capacitance is short circuited find V across inductor
Answer» In a series LCR circuit the voltage across C,R and L are 10V each. If the capacitance is short circuited find V across inductor

Discussion

4883.	what is coulomb's law in vector form?
Answer» what is coulomb's law in vector form?

Discussion

4884.	A wheel is free to rotate about its own axis without friction. A rope is wound the wheel. If other end of rope is pulled with around constant force then true statement from the following is
Answer» A wheel is free to rotate about its own axis without friction. A rope is wound the wheel. If other end of rope is pulled with around constant force then true statement from the following is

Discussion

4885.	At t=0, a particle at the origin has a velocity of 15m/s at 37^° above the horizontal x axis. at t=5s,it is at x=20m and y=35m and its velocity is 30m/s at 53^° above the horizontal .find a) its average velocity b) its average acceleration
Answer» At t=0, a particle at the origin has a velocity of 15m/s at 37^° above the horizontal x axis. at t=5s,it is at x=20m and y=35m and its velocity is 30m/s at 53^° above the horizontal .find a) its average velocity b) its average acceleration

Discussion

4886.	A monochromatic light of wavelength x is incident on an isolated metallic sphere of radius a. The threshold wavelength is x1 which is larger than x. Find the number of photoelectrons emitted before the emission of photoelectrons stop.
Answer» A monochromatic light of wavelength x is incident on an isolated metallic sphere of radius a. The threshold wavelength is x1 which is larger than x. Find the number of photoelectrons emitted before the emission of photoelectrons stop.

Discussion

4887.	A bar of copper of length 75 cm and a bar of steel of length 125 cm are joined together end to end. Both are of circular cross-section with diameter 2 cm. The free ends of the copper and the steel bars are maintained at 100∘C and 0∘C respectively. The curved surfaces of the bars are thermally insulated. What is the temperature of the copper - steel junction?[Take:KCu=386 Js−1m−1∘C−1Ksteel=46 Js−1m−1∘C−1]
Answer» A bar of copper of length $75 cm$ and a bar of steel of length $125 cm$ are joined together end to end. Both are of circular cross-section with diameter $2 cm$ . The free ends of the copper and the steel bars are maintained at $100^{\circ} C$ and $0^{\circ} C$ respectively. The curved surfaces of the bars are thermally insulated. What is the temperature of the $copper - steel$ junction? $[Take : K_{Cu} = 386 {Js}^{- 1} m^{- 1}^{\circ} C^{- 1} K_{steel} = 46 {Js}^{- 1} m^{- 1}^{\circ} C^{- 1}]$

Discussion

4888.	Calculate the sum of the spin only magnetic moments of K3[Fe(oxalate)3] and K3[Ru(oxalate)3].
Answer» Calculate the sum of the spin only magnetic moments of $K_{3} [F e {(oxalate)}_{3}]$ and $K_{3} [R u {(oxalate)}_{3}]$ .

Discussion

4889.	certain amount of an ideal gas contained in a closed vessel . the vessel is moving with cons†an t velocity v , the molecular mass of the gas is M . the rise in temperature when the vessel is suddenly stopped is
Answer» certain amount of an ideal gas contained in a closed vessel . the vessel is moving with cons†an t velocity v , the molecular mass of the gas is M . the rise in temperature when the vessel is suddenly stopped is

Discussion

4890.	An air bubble in sphere of 4 cm diameter appears 1 cm from surface nearest to eye when looked along diameter. If reractive index of sphere is 1.5, calculate the distance of bubble from refracting surface.
Answer» An air bubble in sphere of 4 cm diameter appears 1 cm from surface nearest to eye when looked along diameter. If reractive index of sphere is 1.5, calculate the distance of bubble from refracting surface.

Discussion

4891.	a block of mass 10 kg is held at rest against a rough vertical wall of coefficeint 0.5 under thr action a force F at an angle of 30 degree .the minimum value of F is
Answer» a block of mass 10 kg is held at rest against a rough vertical wall of coefficeint 0.5 under thr action a force F at an angle of 30 degree .the minimum value of F is

Discussion

4892.	A body cools from 80∘C to 50∘C in 5 min. If the temperature of the surroundings is 20∘C then calculate the time it takes to cool from 60∘C to 30∘C.
Answer» A body cools from $80^{\circ} C$ to $50^{\circ} C$ in $5 min$ . If the temperature of the surroundings is $20^{\circ} C$ then calculate the time it takes to cool from $60^{\circ} C$ to $30^{\circ} C$ .

Discussion

4893.	On applying a force F, point P is displaced vertically down by 'y' from equilibrium position. Find the applied force F in terms of 'y' if the point A is displaced by y2 due to application of F.
Answer» On applying a force $F$ , point $P$ is displaced vertically down by 'y' from equilibrium position. Find the applied force $F$ in terms of 'y' if the point $A$ is displaced by $\frac{y}{2}$ due to application of $F$ .

Discussion

4894.	The value of Plank's constant is 6.63 × 10-34 Js. The speed of light is 3×1017 nm s-1. Which value is closest with frequency of 6×1015 s-1 ?
Answer» The value of Plank's constant is 6.63 × 10^-34 Js. The speed of light is 3×10¹⁷ nm s^-1. Which value is closest with frequency of 6×10¹⁵ s^-1 ?

Discussion

4895.	A plane simple harmonic progressive wave of wavelength 120 cm and speed 34800 cm/sec is incident normally on a plane surface which is a perfect reflector of sound. Stationary waves are formed. The ratio of the amplitudes of vibration at points distant (i) 10 cm and (ii) 30 cm from the reflector is:
Answer» A plane simple harmonic progressive wave of wavelength $120 cm$ and speed $34800 cm/sec$ is incident normally on a plane surface which is a perfect reflector of sound. Stationary waves are formed. The ratio of the amplitudes of vibration at points distant (i) $10 cm$ and (ii) $30 cm$ from the reflector is:

Discussion

4896.	A particle passes a given point moving downwards with a velocity of 50m/s. How long before this was it moving upwards at the same rate
Answer» A particle passes a given point moving downwards with a velocity of 50m/s. How long before this was it moving upwards at the same rate

Discussion

4897.	At the centre of a cubical box, a charge +Q is placed. The value of total flux that is coming out of a wall is
Answer» At the centre of a cubical box, a charge $+ Q$ is placed. The value of total flux that is coming out of a wall is

Discussion

4898.	31.The charge stored in 2uF capacitor is
Answer» 31.The charge stored in 2uF capacitor is

Discussion

4899.	A rod of length 4 m is suspended from two wiresas shown in figure. One of them is made of steeland other of copper of cross-sectional area 10-2m2and 4 x 10-2 m2. Find distance x if equal stress isexperienced by both the wires (Yand Ycopper=2x 1011 N/m2Steel1.1 x 1011 N/m2SteelCopperW(2) 3.5 m(1) 2 m(4) 3 m(3) 3.2 m
Answer» A rod of length 4 m is suspended from two wiresas shown in figure. One of them is made of steeland other of copper of cross-sectional area 10-2m2and 4 x 10-2 m2. Find distance x if equal stress isexperienced by both the wires (Yand Ycopper=2x 1011 N/m2Steel1.1 x 1011 N/m2SteelCopperW(2) 3.5 m(1) 2 m(4) 3 m(3) 3.2 m

Discussion

4900.	Bars of 250mm length and 25mm diameter are to be turned on a lathe with a feed of 0.2mm/rev. Each regrinding of the tool costs is Rs.20.The time required for each tool chnage is 1 min. Tool life equation is given as VT02=24 (where cutting speed V is in /(m/min\) and tool life T is in min). The optimum tool cost per piece for maximum production rate is Rs(round off to 2 decimal places).
Answer» Bars of $250 m m$ length and $25 m m$ diameter are to be turned on a lathe with a feed of $0.2 m m / r e v$ . Each regrinding of the tool costs is Rs.20.The time required for each tool chnage is 1 min. Tool life equation is given as $V T^{02} = 24$ (where cutting speed $V$ is in /(m/min\) and tool life $T$ is in $m i n$ ). The optimum tool cost per piece for maximum production rate is $R s$ (round off to $2$ decimal places).

Discussion

Explore topic-wise InterviewSolutions in .

Calculate the speed of sound in oxygen from the following data. The mass of 22.4 litre of oxygen at STP (T = 273 K and P = 1.0× 105 N m−2) is 32g, the molar heat capacity of oxygen at constant volume is CV = 2.5 R and that at constant pressure is Cp = 3.5 R.

44.If separate samples of argon methane nitrogen and carvon dioxide all at the same intial temperature and pressyre and expanded adibatically reversiy to double thier original volume then which of the following gases have high temperature as final temperature

how to take VERNIER SCALE READING and find length of object ?

Find the magnetic field at a point which is at 2 m on perpendicular bisector of finite current carrying wire of length 6 m. If the current of 10A is flowing as shown in the figure, then which of the following options is the correct magnetic field at that point.

34.Reading shown by the hot wire voltmeter used in the circuit here is____

Eight identical resistors each of resistance r are connected along edges of a pyramid having square base ABCD as shown in figure.The equivalent resistance between A and O is

A closed organ pipe has a length l. The air in it is vibrating in third overtone with maximum displacement amplitude of a. The displacement amplitude at distance l/7 from the closed end of the pipe will be

A wave is represented by y=0.1sin(100πt−kx), where y,t,x are in SI units. If wave velocity is 100 m/s, its wave number is

A bullet moving with a velocity of 100 m/s can just penetrate two planks of equal thickness. The number of such planks penetrated by the same bullet, when the velocity is doubled, will be

For the two parallel rays (AB and DE) of same wavelength λ, BD is the wavefront. The phase difference of these two rays at point D is

Helium in a piston/cylinder at 27∘C, 100 kPa is brought to 400 K in a reversible polytropic process with exponent n=1.25. Helium can be assumed to be an ideal gas with constant specific heat capacity. Find the work done per unit mass of gas. Assume R for helium =2.07 kJ/kg K

A car moving along a straight highway with speed of 126 km h¯¹ is brought to a stop within a distance of 200 m. What is the retardation of the car (assumed uniform), and how long does it take for the car to stop ?

39. If m1=10kg;m2=4kg;m3:2kg,the acceleration of the system is ?

A convex mirror has the largest field of view among all the mirrors. This property is used in

Light of wavelength 200 nm shines on an aluminium, 4.20 eV is required to eject an electron. What is the kinetic energy of the fastest ejected electrons in eV? (take h=6.6×10−34 Js)

28. In a Bohrs model of an atom, when an electron jumps from n = 1 to n = 3, how much energy will be emitted or absorbed?

Area bounded by y=xsin x and x- axis between x=0 and x=2π, is

A particle is projected upward from the surface of earth (radius = R) with a speed equal to the orbital speed of a satellite near the earth's surface. The height to which it would rise is

A electron gets emitted from the surface of a tungsten filament whose work function is 43.6ev. if the emitted electron escapes with a velocity of 2\ast10^6 m/s . calculate energy of incident radiation

In a medium in which a transverse progressive wave is travelling, the phase difference between two points with a separation of 1.25 cm is (π/4). If the frequency of wave is 1000 Hz, its velocity in m/s will be

Two particles having masses m1 and m2are situated in a plane perpendicular to line AB at a distance ofr1and r2 respectively as shown. Find the moment of intertia about axis passing through centre of mass and perpendicular to line joining m1 and m2

33.With what speed a ball would be projected upwards so that distance travelled in 5th and 6th would be equal A) 49 m/s B)98 m/s C)58 m/s. D)none of these

1. Electrochemical series

What is the phase difference between I and E if E=E0sin(ωt) and I=I0cos(ωt+π3)?

A point charge q moves with velocity v along a straight line. Displacement current density at a point located at a distance r from charge and in the line of motion of the charge will be

A player kicks a football at an angle of 45∘ with a velocity of 20 ms−1. A second player 60 m away along the direction of kick starts running to receive the ball at that instant. Find the speed with which second player should run to reach the ball before it hits the ground (g=10 ms−2)

In a series LCR circuit the voltage across C,R and L are 10V each. If the capacitance is short circuited find V across inductor

what is coulomb's law in vector form?

A wheel is free to rotate about its own axis without friction. A rope is wound the wheel. If other end of rope is pulled with around constant force then true statement from the following is

At t=0, a particle at the origin has a velocity of 15m/s at 37^° above the horizontal x axis. at t=5s,it is at x=20m and y=35m and its velocity is 30m/s at 53^° above the horizontal .find a) its average velocity b) its average acceleration

A monochromatic light of wavelength x is incident on an isolated metallic sphere of radius a. The threshold wavelength is x1 which is larger than x. Find the number of photoelectrons emitted before the emission of photoelectrons stop.

Calculate the sum of the spin only magnetic moments of K3[Fe(oxalate)3] and K3[Ru(oxalate)3].

certain amount of an ideal gas contained in a closed vessel . the vessel is moving with cons†an t velocity v , the molecular mass of the gas is M . the rise in temperature when the vessel is suddenly stopped is

An air bubble in sphere of 4 cm diameter appears 1 cm from surface nearest to eye when looked along diameter. If reractive index of sphere is 1.5, calculate the distance of bubble from refracting surface.

a block of mass 10 kg is held at rest against a rough vertical wall of coefficeint 0.5 under thr action a force F at an angle of 30 degree .the minimum value of F is

A body cools from 80∘C to 50∘C in 5 min. If the temperature of the surroundings is 20∘C then calculate the time it takes to cool from 60∘C to 30∘C.

On applying a force F, point P is displaced vertically down by 'y' from equilibrium position. Find the applied force F in terms of 'y' if the point A is displaced by y2 due to application of F.

The value of Plank's constant is 6.63 × 10-34 Js. The speed of light is 3×1017 nm s-1. Which value is closest with frequency of 6×1015 s-1 ?

A plane simple harmonic progressive wave of wavelength 120 cm and speed 34800 cm/sec is incident normally on a plane surface which is a perfect reflector of sound. Stationary waves are formed. The ratio of the amplitudes of vibration at points distant (i) 10 cm and (ii) 30 cm from the reflector is:

A particle passes a given point moving downwards with a velocity of 50m/s. How long before this was it moving upwards at the same rate

At the centre of a cubical box, a charge +Q is placed. The value of total flux that is coming out of a wall is

31.The charge stored in 2uF capacitor is