50278 + Interview Questions in Physics

1.	A steel wire of cross-sectional area 0.5 mm2 is held between two fixed supports. If the wire is just taut at 20∘ C, determine the tension when the temperature falls to 0∘ C. Coefficient of linear expansion of steel is 1.2×10−5 ∘C−1 and its Young's modulus is 2.0×1011 Nm−2
Answer» A steel wire of cross-sectional area $0.5 m m^{2}$ is held between two fixed supports. If the wire is just taut at $20^{\circ} C$ , determine the tension when the temperature falls to $0^{\circ} C$ . Coefficient of linear expansion of steel is $1.2 \times 10^{- 5}^{\circ} C^{- 1}$ and its Young's modulus is $2.0 \times 10^{11} N m^{- 2}$

Discussion

2.	Doubly ionized helium ions are projected with a speed of 10 km s−1 in a direction perpendicular to a uniform magnetic field of magnitude 1.0 T. Find (a) the force acting on an ion, (b) the radius of the circle in which it circulates and (c) the time taken by an ion to complete the circle.
Answer» Doubly ionized helium ions are projected with a speed of $10 k m s^{- 1}$ in a direction perpendicular to a uniform magnetic field of magnitude 1.0 T. Find (a) the force acting on an ion, (b) the radius of the circle in which it circulates and (c) the time taken by an ion to complete the circle.

Discussion

3.	a wave function expressing the displacement (Y) as a function of its position (x) and time (t) is given as Y=Alog(bx+Ct). Which of the following has dimensions different from other: 1.YC 2.AC 3.C/b 4.bC
Answer» a wave function expressing the displacement (Y) as a function of its position (x) and time (t) is given as Y=Alog(bx+Ct). Which of the following has dimensions different from other: 1.YC 2.AC 3.C/b 4.bC

3.

a wave function expressing the displacement (Y) as a function of its position (x) and time (t) is given as Y=Alog(bx+Ct). Which of the following has dimensions different from other: 1.YC 2.AC 3.C/b 4.bC

Answer»

a wave function expressing the displacement (Y) as a function of its position (x) and time (t) is given as Y=Alog(bx+Ct). Which of the following has dimensions different from other:

1.YC

2.AC

3.C/b

4.bC

Discussion

4.	Sir in ktg pressure derivation why we take time taken between two successive collisions instead of one collisions?
Answer» Sir in ktg pressure derivation why we take time taken between two successive collisions instead of one collisions?

Discussion

5.	Define electric feild intensity and give its unit.
Answer» Define electric feild intensity and give its unit.

Discussion

6.	Consider the following statements about sound passing through a gas. (A) The pressure of the gas at a point oscillates over time. (B) The position of a small layer of the gas oscillates over time.
Answer» Consider the following statements about sound passing through a gas. (A) The pressure of the gas at a point oscillates over time. (B) The position of a small layer of the gas oscillates over time.

6.

Consider the following statements about sound passing through a gas. (A) The pressure of the gas at a point oscillates over time. (B) The position of a small layer of the gas oscillates over time.

Answer»

Consider the following statements about sound passing through a gas.

(A) The pressure of the gas at a point oscillates over time.

(B) The position of a small layer of the gas oscillates over time.

Discussion

7.	Figure (34 - E7) shows a rod PQ of length 20.0 cm and mass 200 g suspended through a fixed point O by two threads of lengths 20.0 cm each. A magnetic field of strength 0.500 T exists in the vicinity of the wire PQ as shown in the figure. The wires connecting PQ with the battery are loose and exert no force on PQ. (a) Find the tension in the threads when the switch S is open. (b) A current of 2.0 A is established when the switch S is closed. Find the tension in the threads now.
Answer» Figure (34 - E7) shows a rod PQ of length 20.0 cm and mass 200 g suspended through a fixed point O by two threads of lengths 20.0 cm each. A magnetic field of strength 0.500 T exists in the vicinity of the wire PQ as shown in the figure. The wires connecting PQ with the battery are loose and exert no force on PQ. (a) Find the tension in the threads when the switch S is open. (b) A current of 2.0 A is established when the switch S is closed. Find the tension in the threads now.

7.

Figure (34 - E7) shows a rod PQ of length 20.0 cm and mass 200 g suspended through a fixed point O by two threads of lengths 20.0 cm each. A magnetic field of strength 0.500 T exists in the vicinity of the wire PQ as shown in the figure. The wires connecting PQ with the battery are loose and exert no force on PQ. (a) Find the tension in the threads when the switch S is open. (b) A current of 2.0 A is established when the switch S is closed. Find the tension in the threads now.

Answer»

Figure (34 - E7) shows a rod PQ of length 20.0 cm and mass 200 g suspended through a fixed point O by two threads of lengths 20.0 cm each. A magnetic field of strength 0.500 T exists in the vicinity of the wire PQ as shown in the figure. The wires connecting PQ with the battery are loose and exert no force on PQ. (a) Find the tension in the threads when the switch S is open. (b) A current of 2.0 A is established when the switch S is closed. Find the tension in the threads now.

Discussion

8.	The structure of a water molecule is shown in figure(9-E1).Find the distance of the centre of mass of the molecule from the centre of the oxygen atom.
Answer» The structure of a water molecule is shown in figure(9-E1).Find the distance of the centre of mass of the molecule from the centre of the oxygen atom.

8.

The structure of a water molecule is shown in figure(9-E1).Find the distance of the centre of mass of the molecule from the centre of the oxygen atom.

Answer»

The structure of a water molecule is shown in figure(9-E1).Find the distance of the centre of mass of the molecule from the centre of the oxygen atom.

Discussion

9.	A sound wave of frequency 100 Hz is travelling in air. The speed of sound in air is 350 m s−1. By how much is the phase changed at a given point in 2.5 ms?
Answer» A sound wave of frequency 100 Hz is travelling in air. The speed of sound in air is 350 m s $^{- 1}$ . By how much is the phase changed at a given point in 2.5 ms?

Discussion

10.	A block hangs from a string wrapped on a disc of radius 20 cm free to rotate about its axis which is fixed in a horizontal position. If the angular speed of the disc is 10 rad/s at some instant, with what speed is the block going down at that instant? (Answer in m/s)
Answer» A block hangs from a string wrapped on a disc of radius $20 cm$ free to rotate about its axis which is fixed in a horizontal position. If the angular speed of the disc is $10 rad/s$ at some instant, with what speed is the block going down at that instant? (Answer in $m/s$ )

Discussion

11.	Genuine : Authentic : : Mirage : ?
Answer» Genuine : Authentic : : Mirage : ?

Discussion

12.	When a potential difference (V) is applied across a conductor, the thermal speed of electrons is proportional to root of T . How ??
Answer» When a potential difference (V) is applied across a conductor, the thermal speed of electrons is proportional to root of T . How ??

Discussion

13.	A man is coming down an inclined plane of angle 30∘ with speed 2√3 m/s. He has to keep his umbrella vertical to protect himself from rain. If the actual magnitude of velocity of rain is 5 m/s, at what angle with vertical should he keep his umbrella when he is at rest?
Answer» A man is coming down an inclined plane of angle $30^{\circ}$ with speed $2 \sqrt{3} m/s$ . He has to keep his umbrella vertical to protect himself from rain. If the actual magnitude of velocity of rain is $5 m/s$ , at what angle with vertical should he keep his umbrella when he is at rest?

Discussion

14.	A particle is projected from the bottom of an inclined plane of angle 30∘ with a velocity of 30 m/s at an angle of 60∘ with the horizontal. Find the time of flight. (Take g=10 m/s2)
Answer» A particle is projected from the bottom of an inclined plane of angle $30^{\circ}$ with a velocity of $30 m/s$ at an angle of $60^{\circ}$ with the horizontal. Find the time of flight. (Take $g = 10 m / s^{2}$ )

Discussion

15.	A wire of 10−3cm2 cross sectional area carries a current of 0.25 A, then current density is
Answer» A wire of $10^{- 3} c m^{2}$ cross sectional area carries a current of 0.25 A, then current density is

Discussion

16.	In Fresnel diffraction, if the distance between the disc and the screen is decreased, the intensity of central bright spot will
Answer» In Fresnel diffraction, if the distance between the disc and the screen is decreased, the intensity of central bright spot will

Discussion

17.	A ball is shot in a long hall having a roof at a height of 10m with 25 m/s at an angle of 37o with the floor. The ball lands on the floor at a distance of ___ from the point of projection. (Assume elastic collision if any)
Answer» A ball is shot in a long hall having a roof at a height of 10m with 25 m/s at an angle of $37^{o}$ with the floor. The ball lands on the floor at a distance of ___ from the point of projection. (Assume elastic collision if any)

Discussion

18.	Two loudspeakers are emitting sound waves of wavelength λ with an initial phase difference of π/2 as shown in the given figure. At what minimum distance from O on line AB, will one hear a maxima?
Answer» Two loudspeakers are emitting sound waves of wavelength $λ$ with an initial phase difference of $π / 2$ as shown in the given figure. At what minimum distance from O on line AB, will one hear a maxima?

Discussion

19.	A body cools from 50∘C to 49.9∘C in 5 sec. It cools from 40∘C to 39.9∘C in t sec. Assuming Newton's law of cooling to be valid and temperature of surroundings to be 30∘C , the value of t will be
Answer» A body cools from $50^{\circ} C$ to ${49.9}^{\circ} C$ in $5 sec$ . It cools from $40^{\circ} C$ to ${39.9}^{\circ} C$ in $t sec$ . Assuming Newton's law of cooling to be valid and temperature of surroundings to be $30^{\circ} C$ , the value of $t$ will be

Discussion

20.	A particle is moving in a circle of radius R in such a way that at any instant, the normal and tangential components of acceleration are equal. If its speed at t=0 is v0, the time taken to complete the first two revolutions is:
Answer» A particle is moving in a circle of radius $R$ in such a way that at any instant, the normal and tangential components of acceleration are equal. If its speed at $t = 0$ is $v_{0}$ , the time taken to complete the first two revolutions is:

Discussion

21.	In the figure, force F=αt. Which of the following represents the acceleration-time graph of both the blocks? (a1 and a2 are the accelerations of blocks m1 and m2 respectively)
Answer» In the figure, force $F = α t$ . Which of the following represents the acceleration-time graph of both the blocks? ( $a_{1}$ and $a_{2}$ are the accelerations of blocks $m_{1}$ and $m_{2}$ respectively)

Discussion

22.	A ball of mass m=1 kg has an initial velocity 10 m/s. A variable force F=20t+30t2 N is applied on the ball for 1 second. Find the final momentum of the ball.
Answer» A ball of mass $m = 1 kg$ has an initial velocity $10 m/s$ . A variable force $F = 20 t + 30 t^{2} N$ is applied on the ball for $1$ second. Find the final momentum of the ball.

Discussion

23.	What is the unit of Capacitive Reactance Xc?
Answer» What is the unit of Capacitive Reactance X_c?

Discussion

24.	How does a charged particle on acceleration radiates energy?
Answer» How does a charged particle on acceleration radiates energy?

Discussion

25.	Three identical capacitors C1,C2 and C3 have a capacitance of 1.0 μF each and they are uncharged initially. They are connected in a circuit as shown in the figure and C1 is then filled completely with a dielectric material of relative permittivity ∈r. The cell electromotive force (emf) Vo=8 V. First, the switch S1 is closed while the switch S2 is kept open. When the capacitor C3 is fully charged, S1 is opened and S2 is closed simultaneously. When all the capacitors reach equilibrium, the charge on C3 is found to be 5 μC. The value of ∈r is
Answer» Three identical capacitors $C_{1}, C_{2}$ and $C_{3}$ have a capacitance of $1.0 μ F$ each and they are uncharged initially. They are connected in a circuit as shown in the figure and $C_{1}$ is then filled completely with a dielectric material of relative permittivity $\in_{r}$ . The cell electromotive force (emf) $V_{o} = 8 V$ . First, the switch $S_{1}$ is closed while the switch $S_{2}$ is kept open. When the capacitor $C_{3}$ is fully charged, $S_{1}$ is opened and $S_{2}$ is closed simultaneously. When all the capacitors reach equilibrium, the charge on $C_{3}$ is found to be $5 μ C$ . The value of $\in_{r}$ is

Discussion

26.	Energy shared in cylindrical region of length l extending from radius R1 to R2 and coaxial with long wire carrying current i is
Answer» Energy shared in cylindrical region of length l extending from radius $R_{1}$ to $R_{2}$ and coaxial with long wire carrying current i is

Discussion

27.	A block of mass of m is projected along the surface of a smooth circular wall with velocity v. What is the value of average normal force exerted by the circular wall on the block during its motion from A to B. Assume uniform speed during the journey.
Answer» A block of mass of $m$ is projected along the surface of a smooth circular wall with velocity $v$ . What is the value of average normal force exerted by the circular wall on the block during its motion from $A$ to $B$ . Assume uniform speed during the journey.

Discussion

28.	Two bodies of masses 3 kg and 5 kg are moving with velocities 25 m/s and 15 m/s towards each other due to mutual force of attraction as shown in the figure. What is the velocity of their center of mass?
Answer» Two bodies of masses $3 kg$ and $5 kg$ are moving with velocities $25 m/s$ and $15 m/s$ towards each other due to mutual force of attraction as shown in the figure. What is the velocity of their center of mass?

Discussion

29.	Find the velocity of the body of mass 2 kg from the momentum-time graph at the end of 5 seconds.
Answer» Find the velocity of the body of mass $2 k g$ from the momentum-time graph at the end of $5$ seconds.

Discussion

30.	Isn't light supposed to have a constant speed of 3×108 m/s? And if it did have different speeds, would it be possible to find its acceleration?
Answer» Isn't light supposed to have a constant speed of $3 \times 10^{8} m / s$ ? And if it did have different speeds, would it be possible to find its acceleration?

Discussion

31.	What is piezo electric property?
Answer» What is piezo electric property?

Discussion

32.	An unmanned space probe is to be thrown with such a velocity that it does not return back to Earth. It should be thrown with:
Answer» An unmanned space probe is to be thrown with such a velocity that it does not return back to Earth. It should be thrown with:

Discussion

33.	If x = 2±0.1 Y= 2±0.2 find the absolute error
Answer» ^{If x = 2±0.1} ^{Y= 2±0.2 find the absolute error}

33.

If x = 2±0.1 Y= 2±0.2 find the absolute error

Answer»

^{If x = 2±0.1}

^{Y= 2±0.2 find the absolute error}

Discussion

34.	Is work done a scalar or a vector? W=F.s. It should be a vector na??
Answer» Is work done a scalar or a vector? W=F.s. It should be a vector na??

34.

Is work done a scalar or a vector? W=F.s. It should be a vector na??

Answer»

Is work done a scalar or a vector? W=F.s.

It should be a vector na??

Discussion

35.	Q. Four identical point charges are placed at the four vertices of a square. The number of null points will be (What is a null point?)
Answer» Q. Four identical point charges are placed at the four vertices of a square. The number of null points will be (What is a null point?)

35.

Q. Four identical point charges are placed at the four vertices of a square. The number of null points will be (What is a null point?)

Answer»

Q. Four identical point charges are placed at the four vertices of a square. The number of null points will be

(What is a null point?)

Discussion

36.	What is photon
Answer» What is photon

Discussion

37.	The Force F is given in terms of times and displacement x by the equation F=AcosBx+CsinDt The dimensional formula of D\B is.....
Answer» The Force F is given in terms of times and displacement x by the equation F=AcosBx+CsinDt The dimensional formula of D\B is.....

Discussion

38.	Determine the escape velocity of a rocket on the far side of a moon of a planet. The radius of the moon is 2.64×106m and its mass is 1.495×1023. The mass of the planet is 1.9×1027kg, and the distance between planet and the moon is 1.071×109m. Include the gravitational effect of planet and neglect the motion of the planet and the moon as they rotate about their CM.
Answer» Determine the escape velocity of a rocket on the far side of a moon of a planet. The radius of the moon is $2.64 \times 10^{6}$ m and its mass is $1.495 \times 10^{23}$ . The mass of the planet is $1.9 \times 10^{27}$ kg, and the distance between planet and the moon is $1.071 \times 10^{9}$ m. Include the gravitational effect of planet and neglect the motion of the planet and the moon as they rotate about their CM.

38.

Determine the escape velocity of a rocket on the far side of a moon of a planet. The radius of the moon is 2.64×106m and its mass is 1.495×1023. The mass of the planet is 1.9×1027kg, and the distance between planet and the moon is 1.071×109m. Include the gravitational effect of planet and neglect the motion of the planet and the moon as they rotate about their CM.

Answer»

Determine the escape velocity of a rocket on the far side of a moon of a planet. The radius of the moon is $2.64 \times 10^{6}$ m and its mass is $1.495 \times 10^{23}$ . The mass of the planet is $1.9 \times 10^{27}$ kg, and the distance between planet and the moon is $1.071 \times 10^{9}$ m. Include the gravitational effect of planet and neglect the motion of the planet and the moon as they rotate about their CM.

Discussion

39.	When vapour condenses into liquid
Answer» When vapour condenses into liquid

Discussion

40.	If a ball of mass 1 kg makes a head-on collision with a ball of an unknown mass initially at rest such that the ball rebounds to one third of its original speed, what is the mass of the other ball?
Answer» If a ball of mass 1 kg makes a head-on collision with a ball of an unknown mass initially at rest such that the ball rebounds to one third of its original speed, what is the mass of the other ball?

Discussion

41.	A student carries out an experiment and plots the V-I graph of three samples of nichrome wire with resistances R1,R2 and R3 respectively. What is the relation between R1,R2 and R3?
Answer» A student carries out an experiment and plots the V-I graph of three samples of nichrome wire with resistances $R_{1}, R_{2}$ and $R_{3}$ respectively. What is the relation between $R_{1}, R_{2}$ and $R_{3}$ ?

Discussion

42.	A particle moves, along a straight line OX. At a time t (in second), the position x (in metre) of the particle from O is given by x=40+4t−t4. Displacement of the particle before coming to rest is
Answer» A particle moves, along a straight line $O X$ . At a time $t$ (in second), the position $x$ (in metre) of the particle from $O$ is given by $x = 40 + 4 t - t^{4}$ . Displacement of the particle before coming to rest is

Discussion

43.	The frequency of revolution of electron in nth Bohr orbit is Vn. The graph between log n and log(VnV1) may be
Answer» The frequency of revolution of electron in $n^{t h}$ Bohr orbit is $V_{n}$ . The graph between $l o g n$ and $l o g (\frac{V_{n}}{V_{1}})$ may be

Discussion

44.	(a) Explain the processes of nuclear fission and nuclear fusion by using the plot of binding energy per nucleon (BE/A) versus the mass number A. (b) A radioactive isotope has a half-life of 10 years. How long will it take for the activity to reduce to 3.125% ?
Answer» (a) Explain the processes of nuclear fission and nuclear fusion by using the plot of binding energy per nucleon (BE/A) versus the mass number A. (b) A radioactive isotope has a half-life of 10 years. How long will it take for the activity to reduce to 3.125% ?

Discussion

45.	A body of mass 5 gm is executing S.H.M. about a point with amplitude 10 cm. Its maximum velocity is 100 cm/sec. Its velocity will be 50 cm/sec at a distance [CPMT 1976]
Answer» A body of mass 5 gm is executing S.H.M. about a point with amplitude 10 cm. Its maximum velocity is 100 cm/sec. Its velocity will be 50 cm/sec at a distance [CPMT 1976]

45.

A body of mass 5 gm is executing S.H.M. about a point with amplitude 10 cm. Its maximum velocity is 100 cm/sec. Its velocity will be 50 cm/sec at a distance [CPMT 1976]

Answer»

A body of mass 5 gm is executing S.H.M. about a point with amplitude 10 cm. Its maximum velocity is 100 cm/sec. Its velocity will be 50 cm/sec at a distance

[CPMT 1976]

Discussion

46.	What is an electric dipole?
Answer» What is an electric dipole?

Discussion

47.	Find the current through the battery in each of the circuits shown in figure (45-E5).
Answer» Find the current through the battery in each of the circuits shown in figure (45-E5).

47.

Find the current through the battery in each of the circuits shown in figure (45-E5).

Answer»

Find the current through the battery in each of the circuits shown in figure (45-E5).

Discussion

48.	State Newton's third law of motion.
Answer» State Newton's third law of motion.

Discussion

49.	Two friends A and B (each weighing 40 kg) are sitting on a friction less platform some distance d apart.A rolls a ball of mass 4 kg on the platform towards B which B catches.Then B rolls the ball towards A and A catches it.The ball keeps on moving back and forth between A and B.The ball has a fixed speed of 5 m/s on the platform.(a) Find the speed of A after he rolls the ball for the first time.(b) Find the speed of A after he catches the ball for the first time.(c) Find the speeds of A and B after the ball has made 5 round trips and is held by A.(d) How many times can A roll the ball ? (e) Where is the centre of mass of the system "A+B+ball" at the end of the nth trip ?
Answer» Two friends A and B (each weighing 40 kg) are sitting on a friction less platform some distance d apart.A rolls a ball of mass 4 kg on the platform towards B which B catches.Then B rolls the ball towards A and A catches it.The ball keeps on moving back and forth between A and B.The ball has a fixed speed of 5 m/s on the platform.(a) Find the speed of A after he rolls the ball for the first time.(b) Find the speed of A after he catches the ball for the first time.(c) Find the speeds of A and B after the ball has made 5 round trips and is held by A.(d) How many times can A roll the ball ? (e) Where is the centre of mass of the system "A+B+ball" at the end of the nth trip ?

Discussion

50.	A part of a circuit in steady state along with the current flowing in the branches, with value of each resistance is shown in figure. What will be the energy stored in the capacitor C0
Answer» A part of a circuit in steady state along with the current flowing in the branches, with value of each resistance is shown in figure. What will be the energy stored in the capacitor $C_{0}$

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

A steel wire of cross-sectional area 0.5 mm2 is held between two fixed supports. If the wire is just taut at 20∘ C, determine the tension when the temperature falls to 0∘ C. Coefficient of linear expansion of steel is 1.2×10−5 ∘C−1 and its Young's modulus is 2.0×1011 Nm−2

Doubly ionized helium ions are projected with a speed of 10 km s−1 in a direction perpendicular to a uniform magnetic field of magnitude 1.0 T. Find (a) the force acting on an ion, (b) the radius of the circle in which it circulates and (c) the time taken by an ion to complete the circle.

a wave function expressing the displacement (Y) as a function of its position (x) and time (t) is given as Y=Alog(bx+Ct). Which of the following has dimensions different from other: 1.YC 2.AC 3.C/b 4.bC

Sir in ktg pressure derivation why we take time taken between two successive collisions instead of one collisions?

Define electric feild intensity and give its unit.

Consider the following statements about sound passing through a gas. (A) The pressure of the gas at a point oscillates over time. (B) The position of a small layer of the gas oscillates over time.

The structure of a water molecule is shown in figure(9-E1).Find the distance of the centre of mass of the molecule from the centre of the oxygen atom.

A sound wave of frequency 100 Hz is travelling in air. The speed of sound in air is 350 m s−1. By how much is the phase changed at a given point in 2.5 ms?

A block hangs from a string wrapped on a disc of radius 20 cm free to rotate about its axis which is fixed in a horizontal position. If the angular speed of the disc is 10 rad/s at some instant, with what speed is the block going down at that instant? (Answer in m/s)

Genuine : Authentic : : Mirage : ?

When a potential difference (V) is applied across a conductor, the thermal speed of electrons is proportional to root of T . How ??

A man is coming down an inclined plane of angle 30∘ with speed 2√3 m/s. He has to keep his umbrella vertical to protect himself from rain. If the actual magnitude of velocity of rain is 5 m/s, at what angle with vertical should he keep his umbrella when he is at rest?

A particle is projected from the bottom of an inclined plane of angle 30∘ with a velocity of 30 m/s at an angle of 60∘ with the horizontal. Find the time of flight. (Take g=10 m/s2)

A wire of 10−3cm2 cross sectional area carries a current of 0.25 A, then current density is

In Fresnel diffraction, if the distance between the disc and the screen is decreased, the intensity of central bright spot will

A ball is shot in a long hall having a roof at a height of 10m with 25 m/s at an angle of 37o with the floor. The ball lands on the floor at a distance of ___ from the point of projection. (Assume elastic collision if any)

Two loudspeakers are emitting sound waves of wavelength λ with an initial phase difference of π/2 as shown in the given figure. At what minimum distance from O on line AB, will one hear a maxima?

A body cools from 50∘C to 49.9∘C in 5 sec. It cools from 40∘C to 39.9∘C in t sec. Assuming Newton's law of cooling to be valid and temperature of surroundings to be 30∘C , the value of t will be

A particle is moving in a circle of radius R in such a way that at any instant, the normal and tangential components of acceleration are equal. If its speed at t=0 is v0, the time taken to complete the first two revolutions is:

In the figure, force F=αt. Which of the following represents the acceleration-time graph of both the blocks? (a1 and a2 are the accelerations of blocks m1 and m2 respectively)

A ball of mass m=1 kg has an initial velocity 10 m/s. A variable force F=20t+30t2 N is applied on the ball for 1 second. Find the final momentum of the ball.

What is the unit of Capacitive Reactance Xc?

How does a charged particle on acceleration radiates energy?

Energy shared in cylindrical region of length l extending from radius R1 to R2 and coaxial with long wire carrying current i is

A block of mass of m is projected along the surface of a smooth circular wall with velocity v. What is the value of average normal force exerted by the circular wall on the block during its motion from A to B. Assume uniform speed during the journey.

Two bodies of masses 3 kg and 5 kg are moving with velocities 25 m/s and 15 m/s towards each other due to mutual force of attraction as shown in the figure. What is the velocity of their center of mass?

Find the velocity of the body of mass 2 kg from the momentum-time graph at the end of 5 seconds.

Isn't light supposed to have a constant speed of 3×108 m/s? And if it did have different speeds, would it be possible to find its acceleration?

What is piezo electric property?

An unmanned space probe is to be thrown with such a velocity that it does not return back to Earth. It should be thrown with:

If x = 2±0.1 Y= 2±0.2 find the absolute error

Is work done a scalar or a vector? W=F.s. It should be a vector na??

Q. Four identical point charges are placed at the four vertices of a square. The number of null points will be (What is a null point?)

What is photon

The Force F is given in terms of times and displacement x by the equation F=AcosBx+CsinDt The dimensional formula of D\B is.....

When vapour condenses into liquid

If a ball of mass 1 kg makes a head-on collision with a ball of an unknown mass initially at rest such that the ball rebounds to one third of its original speed, what is the mass of the other ball?

A student carries out an experiment and plots the V-I graph of three samples of nichrome wire with resistances R1,R2 and R3 respectively. What is the relation between R1,R2 and R3?

A particle moves, along a straight line OX. At a time t (in second), the position x (in metre) of the particle from O is given by x=40+4t−t4. Displacement of the particle before coming to rest is

The frequency of revolution of electron in nth Bohr orbit is Vn. The graph between log n and log(VnV1) may be

(a) Explain the processes of nuclear fission and nuclear fusion by using the plot of binding energy per nucleon (BE/A) versus the mass number A. (b) A radioactive isotope has a half-life of 10 years. How long will it take for the activity to reduce to 3.125% ?

A body of mass 5 gm is executing S.H.M. about a point with amplitude 10 cm. Its maximum velocity is 100 cm/sec. Its velocity will be 50 cm/sec at a distance [CPMT 1976]

What is an electric dipole?

Find the current through the battery in each of the circuits shown in figure (45-E5).

State Newton's third law of motion.

A part of a circuit in steady state along with the current flowing in the branches, with value of each resistance is shown in figure. What will be the energy stored in the capacitor C0