50278 + Interview Questions in Physics

1.	a charged particle of mass m and charge q enters into a magnetic field B with a velocity v at an angle theta with B. choose the incorrect option.a) the kinetic energy of particle will not change if theta is not equal to0.b)momentum of the particle will not change if theta is not equal to 0c)the particle movves in a circle of radius mv/qv if theta equals 90
Answer» a charged particle of mass m and charge q enters into a magnetic field B with a velocity v at an angle theta with B. choose the incorrect option. a) the kinetic energy of particle will not change if theta is not equal to0. b)momentum of the particle will not change if theta is not equal to 0 c)the particle movves in a circle of radius mv/qv if theta equals 90

Discussion

2.	A stone of mass 1kg tied to a light string of length l=10m is whirling in a circular path in the vertical plane. if the ratio of the maximum to minimum tensions in the string is 3,find the speeds of the stone at lowest and highest points.
Answer» A stone of mass 1kg tied to a light string of length l=10m is whirling in a circular path in the vertical plane. if the ratio of the maximum to minimum tensions in the string is 3,find the speeds of the stone at lowest and highest points.

Discussion

3.	A charged ring of mass m=50 grm, charge 2 coulomb and radius R =2m is placed on a smooth horizontal surface. A magnetic field varying with time at a rate of (0.2 t) Tesla/ sec is applied on to the ring in a direction normalto the surface of ring. Find the angular speed attained in a time t1=10 sec.
Answer» A charged ring of mass m=50 grm, charge 2 coulomb and radius R =2m is placed on a smooth horizontal surface. A magnetic field varying with time at a rate of (0.2 t) Tesla/ sec is applied on to the ring in a direction normalto the surface of ring. Find the angular speed attained in a time t1=10 sec.

Discussion

4.	35. A sKater of mass m standing on ice throws a stone of mass M with a velocity v in horizontal direction.The distance sKater will move back(the coefficient of friction b/w ice and sKater is u)
Answer» 35. A sKater of mass m standing on ice throws a stone of mass M with a velocity v in horizontal direction.The distance sKater will move back(the coefficient of friction b/w ice and sKater is u)

Discussion

5.	The forbidden energy band gap in conductors, semiconductors and insulators is EG1,EG2 and EG3 respectively. The relation among them is
Answer» The forbidden energy band gap in conductors, semiconductors and insulators is $E G_{1}, E G_{2} and E G_{3}$ respectively. The relation among them is

Discussion

6.	An object is moving with a velocity of 2^i+3^j+6^k. A plane mirror whose reflecting surface is parallel to y−z plane is moving with a velocity of ^i+^j+^k. What is the velocity of the image as seen by a stationary observer?
Answer» An object is moving with a velocity of $2^i + 3^j + 6^k$ . A plane mirror whose reflecting surface is parallel to $y - z$ plane is moving with a velocity of $^i +^j +^k$ . What is the velocity of the image as seen by a stationary observer?

Discussion

7.	A ray of light is incident on one face of an equilateral prism. When the angle of incidence is 90∘, the refracted ray from the first face goes undeviated from the second face. Find the refractive index of the material of the prism.1.15
Answer» A ray of light is incident on one face of an equilateral prism. When the angle of incidence is $90^{\circ}$ , the refracted ray from the first face goes undeviated from the second face. Find the refractive index of the material of the prism. 1.15

Discussion

8.	A ball is projected with a velocity 'v' so that its range on a horizontal plane is twice the greatest height attained by the projectile. Then, its range is
Answer» A ball is projected with a velocity 'v' so that its range on a horizontal plane is twice the greatest height attained by the projectile. Then, its range is

Discussion

9.	The number of possible modes of natural oscillations of air column in a pipe closed at one end of length 170 cm below frequency 1450 Hz are [velocity of sound =340 ms−1]
Answer» The number of possible modes of natural oscillations of air column in a pipe closed at one end of length $170 cm$ below frequency $1450 Hz$ are [velocity of sound $= 340 {ms}^{- 1}$ ]

Discussion

10.	a bomb of mass 3 kg at rest
Answer» a bomb of mass 3 kg at rest

Discussion

11.	in a vernier capillar ,one main scale division is x cm and n divisions of the vernier scale coincides with (n-1) divisions of the main scale .the least count (in)
Answer» in a vernier capillar ,one main scale division is x cm and n divisions of the vernier scale coincides with (n-1) divisions of the main scale .the least count (in)

Discussion

12.	Two pistons having low thermal conductivity divide an adiabatic container in three equal parts as shown. An ideal gas is present in the three parts A, B and C having initial pressures as shown and same temperatures. Now the pistons are released. Then the final equilibrium length of part A after long time will be
Answer» Two pistons having low thermal conductivity divide an adiabatic container in three equal parts as shown. An ideal gas is present in the three parts A, B and C having initial pressures as shown and same temperatures. Now the pistons are released. Then the final equilibrium length of part A after long time will be

Discussion

13.	find out the position and velocity of an object at an ins†an t T if it is acted upon by a cons†an t power P
Answer» find out the position and velocity of an object at an ins†an t T if it is acted upon by a cons†an t power P

Discussion

14.	a quantity of electriccharge that brings about the depoaition of 4.5g Al from Al+3 at the catjode will also produce the following volume(stp)of Hw from H+ at the cathode a)44.8l b)22.7l c)11.2 d)5.6 a
Answer» a quantity of electriccharge that brings about the depoaition of 4.5g Al from Al+3 at the catjode will also produce the following volume(stp)of Hw from H+ at the cathode a)44.8l b)22.7l c)11.2 d)5.6 a

Discussion

15.	A particle moving with uniform acceleration along a straight. Its velocities at points A and B are respectively 7m/s and 17 m/s. M is midpoint of A and B. If t_{1 }is the time taken to go from A to M and t_2 the time taken to go from M to B, then ratio of t_1:t_2is equal to
Answer» A particle moving with uniform acceleration along a straight. Its velocities at points A and B are respectively 7m/s and 17 m/s. M is midpoint of A and B. If t_{1 }is the time taken to go from A to M and t_2 the time taken to go from M to B, then ratio of t_1:t_2is equal to

Discussion

16.	Equal masses of two liquids having densities d1 and d2 are mixed together. The density of the resulting mixture is
Answer» Equal masses of two liquids having densities $d_{1}$ and $d_{2}$ are mixed together. The density of the resulting mixture is

Discussion

17.	The magnetic field at the origin due to the current flowing in the wire is
Answer» The magnetic field at the origin due to the current flowing in the wire is

Discussion

18.	42.The time period of mass M when displaced from its equilibrium position and then released for the system as shown in fig is
Answer» 42.The time period of mass M when displaced from its equilibrium position and then released for the system as shown in fig is

Discussion

19.	{ 13. A block of mass }m moving at a speed v }}{ compresses a spring through a distance }x before }} its speed is haved. Find the spring constant of the } spring.
Answer» { 13. A block of mass }m moving at a speed v }}{ compresses a spring through a distance }x before }} its speed is haved. Find the spring constant of the } spring.

Discussion

20.	Upon a six fold increase in the external resistanceof a circuit, the voltage across the terminalsbattery increases from 5V to 10V. The e.m.f. Ofbattery is
Answer» Upon a six fold increase in the external resistanceof a circuit, the voltage across the terminalsbattery increases from 5V to 10V. The e.m.f. Ofbattery is

Discussion

21.	With doubling the frequency of revolution the magnetic moment of electron doubles. Why?
Answer» With doubling the frequency of revolution the magnetic moment of electron doubles. Why?

Discussion

22.	The bob A of a pendulum released from a height h hits head-on another bob B of the same mass of an identical pendulum initially at rest. What is the result of this collision? Assume the collision to be elastic.
Answer» The bob A of a pendulum released from a height h hits head-on another bob B of the same mass of an identical pendulum initially at rest. What is the result of this collision? Assume the collision to be elastic.

Discussion

23.	Figure shows a system of three concentric metal shells A, B and C with radii a,2a and 3a respectively. Shell B is earthed and shellC is given a charge Q. Now, if shell C is connected to shell A, then the final charge on the shell B is equal to
Answer» Figure shows a system of three concentric metal shells $A, B$ and $C$ with radii $a, 2 a$ and $3 a$ respectively. Shell $B$ is earthed and shell $C$ is given a charge $Q$ . Now, if shell $C$ is connected to shell $A$ , then the final charge on the shell $B$ is equal to

Discussion

24.	Question 1 (c)Fill in the blank.If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the _________ terminal of the battery.
Answer» Question 1 (c) Fill in the blank. If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the _________ terminal of the battery.

24.

Question 1 (c)Fill in the blank.If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the _________ terminal of the battery.

Answer»

Question 1 (c)

Fill in the blank.

If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the _________ terminal of the battery.

Discussion

25.	39.Find minimum possible magnitude of force acting between two point charges separated by 10 cm in a free space?
Answer» 39.Find minimum possible magnitude of force acting between two point charges separated by 10 cm in a free space?

Discussion

26.	If a ball is thrown vertically upwards with speed u, the distance covered during the last t seconds of its ascent is
Answer» If a ball is thrown vertically upwards with speed $u$ , the distance covered during the last $t$ seconds of its ascent is

Discussion

27.	A ring is rotating with an angular acceleration given by α=4t3−32t2, where t is time. Find the equation of angular speed ω if the ring starts from rest.
Answer» A ring is rotating with an angular acceleration given by $α = 4 t^{3} - \frac{3}{2} t^{2}$ , where $t$ is time. Find the equation of angular speed $ω$ if the ring starts from rest.

Discussion

28.	The refractive index of a prism is 2. This prism can have A mximum refracting angle of
Answer» The refractive index of a prism is 2. This prism can have A mximum refracting angle of

Discussion

29.	If arcs of same length in two circles, subtends angles of 90∘ and 135∘ at their centers, then the ratio of their radii is
Answer» If arcs of same length in two circles, subtends angles of $90^{\circ}$ and $135^{\circ}$ at their centers, then the ratio of their radii is

Discussion

30.	If the units of length and force are increased to 4 times then the unit of energy will increase to how many times
Answer» If the units of length and force are increased to 4 times then the unit of energy will increase to how many times

Discussion

31.	Two equal masses m and m are hung from a balance whose scale pans differ in vertical height by 'h'. The error in weighing in terms of density of the earth ρ is :
Answer» Two equal masses m and m are hung from a balance whose scale pans differ in vertical height by 'h'. The error in weighing in terms of density of the earth $ρ$ is :

Discussion

32.	The radius of a sphere shrinks from 10 to 9.8 cm. The approximate decrease(in cm3)in its volume is
Answer» The radius of a sphere shrinks from $10$ to $9.8$ cm. The approximate decrease $($ in cm $^{3})$ in its volume is

Discussion

33.	A wire having a linear mass density 5.0×10−3 kg/m is stretched between two rigid supports with tension of 450 N. The wire reasonates at frequency 400 Hz. The next higher frequency at which the wire resonates is 500 Hz. The length of the wire will be
Answer» A wire having a linear mass density $5.0 \times 10^{- 3} k g / m$ is stretched between two rigid supports with tension of $450 N$ . The wire reasonates at frequency $400 H z$ . The next higher frequency at which the wire resonates is $500 H z$ . The length of the wire will be

Discussion

34.	A block of mass 2.0 kg slides on a rough surface. At t=0, its speed is 2.0 m/s. It stops after covering a distance of 20 cm because of the friction exerted by the surface on it. Find the work done by friction.
Answer» A block of mass $2.0 kg$ slides on a rough surface. At $t = 0$ , its speed is $2.0 m/s$ . It stops after covering a distance of $20 cm$ because of the friction exerted by the surface on it. Find the work done by friction.

Discussion

35.	The minimum and maximum distances of a planet revolving around sun are r and R. If the minimum speed of planet on its trajectory is v0, its maximum speed will be
Answer» The minimum and maximum distances of a planet revolving around sun are $r$ and $R$ . If the minimum speed of planet on its trajectory is $v_{0}$ , its maximum speed will be

Discussion

36.	A particle of mass M is released in vertical plane from a point P at x = x0 on the axis it falls vertically along the y-axis. Find the torque τ acting on the particle at a time t about origin?
Answer» A particle of mass M is released in vertical plane from a point P at $x$ = $x_{0}$ on the axis it falls vertically along the y-axis. Find the torque $τ$ acting on the particle at a time t about origin?

36.

A particle of mass M is released in vertical plane from a point P at x = x0 on the axis it falls vertically along the y-axis. Find the torque τ acting on the particle at a time t about origin?

Answer»

A particle of mass M is released in vertical plane from a point P at $x$ = $x_{0}$ on the axis it falls vertically

along the y-axis. Find the torque $τ$ acting on the particle at a time t about origin?

Discussion

37.	the charge Q is uniformly distributed throughtout the volume of uniformly charged non conducting solid sphere of radius R.the dielectric constant of the medium is 1.the electric field intensity at a distance r (
Answer» the charge Q is uniformly distributed throughtout the volume of uniformly charged non conducting solid sphere of radius R.the dielectric constant of the medium is 1.the electric field intensity at a distance r (

Discussion

38.	a fan is rotating with speed of 360rev/minute. comes to rest in 6s,on switching of the switch. the number of revolution made by it before coming to rest is
Answer» a fan is rotating with speed of 360rev/minute. comes to rest in 6s,on switching of the switch. the number of revolution made by it before coming to rest is

Discussion

39.	How the net dipole moment of an atom for diamagnetic material is zero?
Answer» How the net dipole moment of an atom for diamagnetic material is zero?

Discussion

40.	For the above problem, the direction of the gravitational intensity at an arbitrary point P is indicated by the arrow (i) d, (ii) e, (iii) f, (iv) g.
Answer» For the above problem, the direction of the gravitational intensity at an arbitrary point P is indicated by the arrow (i) d, (ii) e, (iii) f, (iv) g.

Discussion

41.	Variation in the value of a current with time is shown in the figure below. The average value of the current in time t = 0 to t = T isनीचे चित्र में समय के साथ धारा के मान में परिवर्तन दर्शाया गया है। समय t = 0 से t = T में धारा का औसत मान है
Answer» Variation in the value of a current with time is shown in the figure below. The average value of the current in time t = 0 to t = T is नीचे चित्र में समय के साथ धारा के मान में परिवर्तन दर्शाया गया है। समय t = 0 से t = T में धारा का औसत मान है

Discussion

42.	A spacecraft engine ejects mass at a rate of 30 kg/s with an exhaust velocity of 3000 m/s. What is the thrust of the engine in vaccum?
Answer» A spacecraft engine ejects mass at a rate of $30 kg/s$ with an exhaust velocity of $3000 m/s$ . What is the thrust of the engine in vaccum?

Discussion

43.	Two tall buildings face each other and are at a distance of 180 m from each other. With what velocity (in m/s) must a ball be thrown horizontally from a window 55 m above the ground in one building, so that it enters a window 10.9 m above the ground in the second building? (Take g=9.8 m/s2)
Answer» Two tall buildings face each other and are at a distance of $180 m$ from each other. With what velocity (in $m/s$ ) must a ball be thrown horizontally from a window $55 m$ above the ground in one building, so that it enters a window $10.9 m$ above the ground in the second building? (Take $g = 9.8 {m/s}^{2}$ )

Discussion

44.	What is dimensionless quantity? Give examples.
Answer» What is dimensionless quantity? Give examples.

Discussion

45.	Which of the following electric field lines configuration is correct for an isolated positive point charge?(Angles shown in the options are between the electric field lines and the tangent at the point of contact.)
Answer» Which of the following electric field lines configuration is correct for an isolated positive point charge? (Angles shown in the options are between the electric field lines and the tangent at the point of contact.)

Discussion

46.	Is a thermal cooker better than a casserole? Support your answer with proper statements.
Answer» Is a thermal cooker better than a casserole? Support your answer with proper statements.

Discussion

47.	95.The vapour density of N2O4 at a certain temperature is 30. What is the dissociation of N2O4 at this temperature?A)0% B )45.5% C)27% D)none
Answer» 95.The vapour density of N2O4 at a certain temperature is 30. What is the dissociation of N2O4 at this temperature?A)0% B )45.5% C)27% D)none

Discussion

48.	Notice these words and expressions in the text. Infer their meanings from the context.
Answer» Notice these words and expressions in the text. Infer their meanings from the context.

Discussion

49.	78.The driver of a car travelling at 20m/s and suddenly sees a big rock on a road at a distance of 20m .to avoid collision should he turn sharply or apply brakes
Answer» 78.The driver of a car travelling at 20m/s and suddenly sees a big rock on a road at a distance of 20m .to avoid collision should he turn sharply or apply brakes

Discussion

50.	A particle of mass m1 is kept at x=0 and another particle of mass m2 at x=d. When a third particle is kept at x=d/4, it experiences no net gravitational force due to the two particles. Find m2m1.
Answer» A particle of mass $m_{1}$ is kept at $x = 0$ and another particle of mass $m_{2}$ at $x = d$ . When a third particle is kept at $x = d / 4$ , it experiences no net gravitational force due to the two particles. Find $\frac{m_{2}}{m_{1}}$ .

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

A stone of mass 1kg tied to a light string of length l=10m is whirling in a circular path in the vertical plane. if the ratio of the maximum to minimum tensions in the string is 3,find the speeds of the stone at lowest and highest points.

A charged ring of mass m=50 grm, charge 2 coulomb and radius R =2m is placed on a smooth horizontal surface. A magnetic field varying with time at a rate of (0.2 t) Tesla/ sec is applied on to the ring in a direction normalto the surface of ring. Find the angular speed attained in a time t1=10 sec.

35. A sKater of mass m standing on ice throws a stone of mass M with a velocity v in horizontal direction.The distance sKater will move back(the coefficient of friction b/w ice and sKater is u)

The forbidden energy band gap in conductors, semiconductors and insulators is EG1,EG2 and EG3 respectively. The relation among them is

An object is moving with a velocity of 2^i+3^j+6^k. A plane mirror whose reflecting surface is parallel to y−z plane is moving with a velocity of ^i+^j+^k. What is the velocity of the image as seen by a stationary observer?

A ray of light is incident on one face of an equilateral prism. When the angle of incidence is 90∘, the refracted ray from the first face goes undeviated from the second face. Find the refractive index of the material of the prism.1.15

A ball is projected with a velocity 'v' so that its range on a horizontal plane is twice the greatest height attained by the projectile. Then, its range is

The number of possible modes of natural oscillations of air column in a pipe closed at one end of length 170 cm below frequency 1450 Hz are [velocity of sound =340 ms−1]

a bomb of mass 3 kg at rest

in a vernier capillar ,one main scale division is x cm and n divisions of the vernier scale coincides with (n-1) divisions of the main scale .the least count (in)

find out the position and velocity of an object at an ins†an t T if it is acted upon by a cons†an t power P

a quantity of electriccharge that brings about the depoaition of 4.5g Al from Al+3 at the catjode will also produce the following volume(stp)of Hw from H+ at the cathode a)44.8l b)22.7l c)11.2 d)5.6 a

A particle moving with uniform acceleration along a straight. Its velocities at points A and B are respectively 7m/s and 17 m/s. M is midpoint of A and B. If t_{1 }is the time taken to go from A to M and t_2 the time taken to go from M to B, then ratio of t_1:t_2is equal to

Equal masses of two liquids having densities d1 and d2 are mixed together. The density of the resulting mixture is

The magnetic field at the origin due to the current flowing in the wire is

42.The time period of mass M when displaced from its equilibrium position and then released for the system as shown in fig is

{ 13. A block of mass }m moving at a speed v }}{ compresses a spring through a distance }x before }} its speed is haved. Find the spring constant of the } spring.

Upon a six fold increase in the external resistanceof a circuit, the voltage across the terminalsbattery increases from 5V to 10V. The e.m.f. Ofbattery is

With doubling the frequency of revolution the magnetic moment of electron doubles. Why?

The bob A of a pendulum released from a height h hits head-on another bob B of the same mass of an identical pendulum initially at rest. What is the result of this collision? Assume the collision to be elastic.

Figure shows a system of three concentric metal shells A, B and C with radii a,2a and 3a respectively. Shell B is earthed and shellC is given a charge Q. Now, if shell C is connected to shell A, then the final charge on the shell B is equal to

Question 1 (c)Fill in the blank.If you pass current through copper sulphate solution, copper gets deposited on the plate connected to the _________ terminal of the battery.

39.Find minimum possible magnitude of force acting between two point charges separated by 10 cm in a free space?

If a ball is thrown vertically upwards with speed u, the distance covered during the last t seconds of its ascent is

A ring is rotating with an angular acceleration given by α=4t3−32t2, where t is time. Find the equation of angular speed ω if the ring starts from rest.

The refractive index of a prism is 2. This prism can have A mximum refracting angle of

If arcs of same length in two circles, subtends angles of 90∘ and 135∘ at their centers, then the ratio of their radii is

If the units of length and force are increased to 4 times then the unit of energy will increase to how many times

Two equal masses m and m are hung from a balance whose scale pans differ in vertical height by 'h'. The error in weighing in terms of density of the earth ρ is :

The radius of a sphere shrinks from 10 to 9.8 cm. The approximate decrease(in cm3)in its volume is

A wire having a linear mass density 5.0×10−3 kg/m is stretched between two rigid supports with tension of 450 N. The wire reasonates at frequency 400 Hz. The next higher frequency at which the wire resonates is 500 Hz. The length of the wire will be

A block of mass 2.0 kg slides on a rough surface. At t=0, its speed is 2.0 m/s. It stops after covering a distance of 20 cm because of the friction exerted by the surface on it. Find the work done by friction.

The minimum and maximum distances of a planet revolving around sun are r and R. If the minimum speed of planet on its trajectory is v0, its maximum speed will be

A particle of mass M is released in vertical plane from a point P at x = x0 on the axis it falls vertically along the y-axis. Find the torque τ acting on the particle at a time t about origin?

the charge Q is uniformly distributed throughtout the volume of uniformly charged non conducting solid sphere of radius R.the dielectric constant of the medium is 1.the electric field intensity at a distance r (

a fan is rotating with speed of 360rev/minute. comes to rest in 6s,on switching of the switch. the number of revolution made by it before coming to rest is

How the net dipole moment of an atom for diamagnetic material is zero?

For the above problem, the direction of the gravitational intensity at an arbitrary point P is indicated by the arrow (i) d, (ii) e, (iii) f, (iv) g.

A spacecraft engine ejects mass at a rate of 30 kg/s with an exhaust velocity of 3000 m/s. What is the thrust of the engine in vaccum?

Two tall buildings face each other and are at a distance of 180 m from each other. With what velocity (in m/s) must a ball be thrown horizontally from a window 55 m above the ground in one building, so that it enters a window 10.9 m above the ground in the second building? (Take g=9.8 m/s2)

What is dimensionless quantity? Give examples.

Which of the following electric field lines configuration is correct for an isolated positive point charge?(Angles shown in the options are between the electric field lines and the tangent at the point of contact.)

Is a thermal cooker better than a casserole? Support your answer with proper statements.

95.The vapour density of N2O4 at a certain temperature is 30. What is the dissociation of N2O4 at this temperature?A)0% B )45.5% C)27% D)none

Notice these words and expressions in the text. Infer their meanings from the context.

78.The driver of a car travelling at 20m/s and suddenly sees a big rock on a road at a distance of 20m .to avoid collision should he turn sharply or apply brakes

A particle of mass m1 is kept at x=0 and another particle of mass m2 at x=d. When a third particle is kept at x=d/4, it experiences no net gravitational force due to the two particles. Find m2m1.