50278 + Interview Questions in Physics

1.	If two conducting spheres are separately charged and then brought in contact, then
Answer» If two conducting spheres are separately charged and then brought in contact, then

Discussion

2.	A glass prism of refractive index 1.5 is immersed in water (refractive index 4/3). A light beam incident normally on the face AB is totally reflected to reach the face BC if
Answer» A glass prism of refractive index 1.5 is immersed in water (refractive index 4/3). A light beam incident normally on the face AB is totally reflected to reach the face BC if

2.

A glass prism of refractive index 1.5 is immersed in water (refractive index 4/3). A light beam incident normally on the face AB is totally reflected to reach the face BC if

Answer»

A glass prism of refractive index 1.5 is immersed in water (refractive index 4/3). A light beam incident normally on the face AB is totally reflected to reach the face BC if

Discussion

3.	The position vectors of the points A,B and C are respectively →a,→b and →c. If P divides −−→AB in the ratio 3:4 and Q divides −−→BC in the ratio 2:1 both externally, then −−→PQ is
Answer» The position vectors of the points $A, B$ and $C$ are respectively $\to a, \to b$ and $\to c .$ If $P$ divides $- - \to A B$ in the ratio $3 : 4$ and $Q$ divides $- - \to B C$ in the ratio $2 : 1$ both externally, then $- - \to P Q$ is

Discussion

4.	A circular track of radius 600 m is to be designed for cars at an average speed of 180 km/hr. What should be the angle of banking of the track?
Answer» A circular track of radius 600 m is to be designed for cars at an average speed of 180 km/hr. What should be the angle of banking of the track?

Discussion

5.	A thin uniform circular ring is rolling down an inclined plane of inclination 30∘ without slipping. Its linear acceleration along the inclined plane will be
Answer» A thin uniform circular ring is rolling down an inclined plane of inclination $30^{\circ}$ without slipping. Its linear acceleration along the inclined plane will be

Discussion

6.	An electric dipole of dipole moment p is lying along uniform electric field E.work done in rotating the dipole by 90 degree is
Answer» An electric dipole of dipole moment p is lying along uniform electric field E.work done in rotating the dipole by 90 degree is

Discussion

7.	Disc of radius a2 is cut out from a disc of radius a. Find x co-ordinate of centre of mass from origin.
Answer» Disc of radius $\frac{a}{2}$ is cut out from a disc of radius $a$ . Find $x$ co-ordinate of centre of mass from origin.

Discussion

8.	44. find the moment of inertia of pair of spheres, each having a mass m and radius r kept in contact about tangent passing through the point of contact
Answer» 44. find the moment of inertia of pair of spheres, each having a mass m and radius r kept in contact about tangent passing through the point of contact

Discussion

9.	A cylinder initially kept at rest on a horizontal rough surface is given an angular velocity 10 rad/s. What is the distance travelled by the centre of mass of the cylinder till it begins pure rolling ?Given: Coefficient of kinetic and static frcition are equal (μ=0.5) and radius of cylinder R=3 m. Also, take g=10 m/s2.
Answer» A cylinder initially kept at rest on a horizontal rough surface is given an angular velocity $10 rad/s$ . What is the distance travelled by the centre of mass of the cylinder till it begins pure rolling ? Given: Coefficient of kinetic and static frcition are equal $(μ = 0.5)$ and radius of cylinder $R = 3 m$ . Also, take $g = 10 {m/s}^{2}$ .

Discussion

10.	Aparallel beam of light of wavelength 500 nm falls on a narrow slitand the resulting diffraction pattern is observed on a screen 1 maway. It is observed that the first minimum is at a distance of 2.5mm from the centre of the screen. Find the width of the slit.
Answer» A parallel beam of light of wavelength 500 nm falls on a narrow slit and the resulting diffraction pattern is observed on a screen 1 m away. It is observed that the first minimum is at a distance of 2.5 mm from the centre of the screen. Find the width of the slit.

Discussion

11.	A wire CD of length l=0.5 m and mass m=1 kg is sliding without friction on conducting rails as shown. The vertical rails are connected together with a resistance R=4 Ω. A uniform magnetic field B=1 T is applied perpendicular to the plane of wires such that CD moves with a constant velocity v. Calculate v(in m/s).(Give integer value only)
Answer» A wire $CD$ of length $l = 0.5 m$ and mass $m = 1 kg$ is sliding without friction on conducting rails as shown. The vertical rails are connected together with a resistance $R = 4 Ω$ . A uniform magnetic field $B = 1 T$ is applied perpendicular to the plane of wires such that $CD$ moves with a constant velocity $v$ . Calculate $v (in m/s)$ . (Give integer value only)

Discussion

12.	Q 35/180 Ajuggler is throwing ball vertically up in airat regular time interval of 1 second. Sixth ball justleaves the hand, when first ball comes back to hishands. Then minimum speed with which he throws theball is (g 10 m/s2)
Answer» Q 35/180 Ajuggler is throwing ball vertically up in airat regular time interval of 1 second. Sixth ball justleaves the hand, when first ball comes back to hishands. Then minimum speed with which he throws theball is (g 10 m/s2)

Discussion

13.	A streetcar moves rectilinearly from station A to the next station B with an acceleration varying according to the law f=a−bx, where a and b are constant, and x is the distance from station A. The distance between the two stations and maximum velocity are
Answer» A streetcar moves rectilinearly from station $A$ to the next station $B$ with an acceleration varying according to the law $f = a - b x$ , where $a$ and $b$ are constant, and $x$ is the distance from station $A$ . The distance between the two stations and maximum velocity are

Discussion

14.	Find acceleration of block B if F=40 N.(Take g=10 m/s2)
Answer» Find acceleration of block $B$ if $F = 40 N$ . (Take $g = 10 {m/s}^{2}$ )

Discussion

15.	Why diamagnetic and paramagnetic substances align themselves in external magnetic field perpendicular and parallel to field respectively?
Answer» Why diamagnetic and paramagnetic substances align themselves in external magnetic field perpendicular and parallel to field respectively?

Discussion

16.	A stone of mass 2 kg is tied to one end of a rope of length 2 m. The other end is fixed to a vertical axis, around which the mass is performing a circular motion with an angular speed of 2π rad/s. Then, tension in the rope (in newtons) will be:
Answer» A stone of mass $2 kg$ is tied to one end of a rope of length $2 m$ . The other end is fixed to a vertical axis, around which the mass is performing a circular motion with an angular speed of $2 π rad/s$ . Then, tension in the rope (in $newtons$ ) will be:

Discussion

17.	A tangential force 10 N acts at the top of a thin spherical shell of mass 2 kg. Find the acceleration of the shell if it rolls without slipping.
Answer» A tangential force $10 N$ acts at the top of a thin spherical shell of mass $2 kg$ . Find the acceleration of the shell if it rolls without slipping.

Discussion

18.	A particle moves in a straight line, so that x =\sqrt t .Then its acceleration is proportional to6.(1) Velocity(2) (Velocity)3/2(3) (Velocity)3(4) (Velocity)2
Answer» A particle moves in a straight line, so that x =\sqrt t .Then its acceleration is proportional to6.(1) Velocity(2) (Velocity)3/2(3) (Velocity)3(4) (Velocity)2

Discussion

19.	The value of the integral ln5∫0ex√ex−1ex+3dx is
Answer» The value of the integral $ln 5 \int 0 \frac{e^{x} \sqrt{e^{x} - 1}}{e^{x} + 3} d x$ is

Discussion

20.	Two balls are thrown simul†an eously.A vertically upwards with a speed of 20m/s from the ground and B, vertically downwards from a height of 40m with the same speed and along the same line of motion. At what points do the two balls collide
Answer» Two balls are thrown simul†an eously.A vertically upwards with a speed of 20m/s from the ground and B, vertically downwards from a height of 40m with the same speed and along the same line of motion. At what points do the two balls collide

Discussion

21.	49.A mirror forms a real image 3 cm high of object 1 cm high if the separation between the image and object is 30 cm find the nature and focal length of mirror used
Answer» 49.A mirror forms a real image 3 cm high of object 1 cm high if the separation between the image and object is 30 cm find the nature and focal length of mirror used

Discussion

22.	A helicopter of mass 1000 kg rises with a vertical acceleration of 15 m s¯² The crew and the passengers weigh 300 kg. Give the magnitude and direction of the (a) force on the floor by the crew and passengers, (b) action of the rotor of the helicopter on the surrounding air, (c) force on the helicopter due to the surrounding air.
Answer» A helicopter of mass 1000 kg rises with a vertical acceleration of 15 m s¯² The crew and the passengers weigh 300 kg. Give the magnitude and direction of the (a) force on the floor by the crew and passengers, (b) action of the rotor of the helicopter on the surrounding air, (c) force on the helicopter due to the surrounding air.

Discussion

23.	If a particle has velocity v(t)=4t+2 m/s, the average speed in 2 sec is
Answer» If a particle has velocity $v (t) = 4 t + 2 m/s$ , the average speed in $2 sec$ is

Discussion

24.	A particle having mass 10 g oscillates according to the equation x=(2.0 cm) sin[100 s−1)t+π.6]. Find (a) the amplitude, the time period and the spring constant (b) the position, the velocity and the acceleration at t=0.
Answer» A particle having mass 10 g oscillates according to the equation $x = (2.0 c m) s i n [100 s^{- 1}) t + π .6] .$ Find (a) the amplitude, the time period and the spring constant (b) the position, the velocity and the acceleration at $t = 0.$

Discussion

25.	The spin angular momentum of an electron is given by:
Answer» The spin angular momentum of an electron is given by:

Discussion

26.	An object thrown vertically upwards from the ground passes the height 5m twice in an interval of 10 sec .time of flight ?
Answer» An object thrown vertically upwards from the ground passes the height 5m twice in an interval of 10 sec .time of flight ?

Discussion

27.	If the centre of parallelopiped formed by −−→PA=2^i−^j+^k,−−→PB=−4^i+2^j−^k,−−→PC=−2^i−^j+2^k is given by position vector 3^i−2^j−2^k, then the position vector of point P is
Answer» If the centre of parallelopiped formed by $- - \to P A = 2^i -^j +^k, - - \to P B = - 4^i + 2^j -^k, - - \to P C = - 2^i -^j + 2^k$ is given by position vector $3^i - 2^j - 2^k,$ then the position vector of point $P$ is

Discussion

28.	In an AC circuit, the instantaneous EMF and current is given by E=100sin30t, i=20sin(30t−π4).In one cycle of AC, the average power consumed by the circuit and the wattles current are, respectively
Answer» In an $AC$ circuit, the instantaneous $EMF$ and current is given by $E = 100 sin 30 t, i = 20 sin (30 t - \frac{π}{4})$ . In one cycle of $AC$ , the average power consumed by the circuit and the wattles current are, respectively

Discussion

29.	A ball is dropped from height h.The total distance covered by the body in last second of its motion is equal to distance covered by it in the first three seconds ,what is the vslue of h.
Answer» A ball is dropped from height h.The total distance covered by the body in last second of its motion is equal to distance covered by it in the first three seconds ,what is the vslue of h.

Discussion

30.	A chain of mass m and length l is placed on a table with one-sixth of it hanging freely from the table edge. The amount of work done to pull the chain on to the table is
Answer» A chain of mass $m$ and length $l$ is placed on a table with one-sixth of it hanging freely from the table edge. The amount of work done to pull the chain on to the table is

Discussion

31.	A sphere of iron and another of wood, both of same radius are placed on the surface of water. State which of the two will sink ? Give reason to your answer.
Answer» A sphere of iron and another of wood, both of same radius are placed on the surface of water. State which of the two will sink ? Give reason to your answer.

Discussion

32.	Escape velocity of an atmospheric particle which is 1000 km above the earth's surface, is (radius of earth is6400 km and g =9.8 m/s2)17(1) 6.5 km/s(2) 8 km/s(3) 10 km/s(4) 11.2 km/sTE
Answer» Escape velocity of an atmospheric particle which is 1000 km above the earth's surface, is (radius of earth is6400 km and g =9.8 m/s2)17(1) 6.5 km/s(2) 8 km/s(3) 10 km/s(4) 11.2 km/sTE

Discussion

33.	how to solve n^{th} second problems in horizontal motion when a body stops under cons†an t deceleration and then reverses its direction.
Answer» how to solve n^{th} second problems in horizontal motion when a body stops under cons†an t deceleration and then reverses its direction.

Discussion

34.	2. A particle of mass M rotates in a circle of radius a with uniform angular speed W. it is viewed from a frame rotating with a uniform angular speed W^°. the centrifugal force on the particle is:
Answer» 2. A particle of mass M rotates in a circle of radius a with uniform angular speed W. it is viewed from a frame rotating with a uniform angular speed W^°. the centrifugal force on the particle is:

Discussion

35.	What are the equations of trajectory motion?
Answer» What are the equations of trajectory motion?

Discussion

36.	Find the radius of gyration for a rectangular lamina having mass m about an axis passing through C.O.M and perpendicular to the plane of lamina. (Given: length, a=4 m; breadth, b=3 m)
Answer» Find the radius of gyration for a rectangular lamina having mass $m$ about an axis passing through C.O.M and perpendicular to the plane of lamina. (Given: $length, a = 4 m; breadth, b = 3 m)$

Discussion

37.	A current carrying ring carrying a constant current 2π A has radius 1 m ,mass 23 kg and having 10 windings is free to rotate about its tangential vertical axis. A uniform magnetic field of it is applied perpendicular to its plane. The minimum angular velocity should be given to the ring in the direction shown, so that it can rotate 3π2 angle in that direction is √x rad s−1. Find x ( Give integer value).
Answer» A current carrying ring carrying a constant current $\frac{2}{π} A$ has radius $1 m$ ,mass $\frac{2}{3} kg$ and having $10$ windings is free to rotate about its tangential vertical axis. A uniform magnetic field of it is applied perpendicular to its plane. The minimum angular velocity should be given to the ring in the direction shown, so that it can rotate $\frac{3 π}{2}$ angle in that direction is $\sqrt{x} {rad s}^{- 1}$ . Find $x$ ( Give integer value).

Discussion

38.	A man wants to reach point B on the opposite bank of a river flowing at a speed u as shown in figure. what minimum speed relative to water should the man have so that he can reach point B?
Answer» A man wants to reach point $B$ on the opposite bank of a river flowing at a speed $u$ as shown in figure. what minimum speed relative to water should the man have so that he can reach point $B$ ?

Discussion

39.	A 20 - kg block attached to a spring of spring constant 5 N m−1 is released from rest at A. The spring at this instant is having an elongation of 1 m. The block is allowed to move in smooth horizontal slot with the help of a constant force 50 N in the rope as shown. The velocity of the block as it reaches B is (assume the rope to be light)
Answer» A 20 - kg block attached to a spring of spring constant 5 N $m^{- 1}$ is released from rest at A. The spring at this instant is having an elongation of 1 m. The block is allowed to move in smooth horizontal slot with the help of a constant force 50 N in the rope as shown. The velocity of the block as it reaches B is (assume the rope to be light)

Discussion

40.	Let u1 be the frequency of the series limit of the Lyman series, u2 be the frequency of the first line of the Lyman series, and u3 be the frequency of the series limit of the Balmer series. Then-
Answer» Let $u_{1}$ be the frequency of the series limit of the Lyman series, $u_{2}$ be the frequency of the first line of the Lyman series, and $u_{3}$ be the frequency of the series limit of the Balmer series. Then-

Discussion

41.	Two short electric dipoles at a certain distanceapply a force F on each other. If the separation is doubled, then the force of interaction between the dipoles, will become approximately
Answer» Two short electric dipoles at a certain distanceapply a force F on each other. If the separation is doubled, then the force of interaction between the dipoles, will become approximately

Discussion

42.	A string of length 1 m and mass 5 g is fixed at both ends. The tension in the string is 8.0 N. The string is set into vibration using an external vibrator of frequency 100 Hz. The separation between successive nodes on the string is close to:
Answer» A string of length $1 m$ and mass $5 g$ is fixed at both ends. The tension in the string is $8.0 N$ . The string is set into vibration using an external vibrator of frequency $100 Hz$ . The separation between successive nodes on the string is close to:

Discussion

43.	The two ends of train moving with constant acceleration pass a certain point with velocities u and 3u the velocity with which middle point of the train passes the same point
Answer» The two ends of train moving with constant acceleration pass a certain point with velocities u and 3u the velocity with which middle point of the train passes the same point

Discussion

44.	Given the set up shown in the figure. Blocks A, B and C have masses mA=M & mB=mC=m. The strings are assumed massless and unstretchable and the pulley is frictionless. There is no friction between block B and the support table, but there is friction between blocks B and C donated by a given coefficient μ. Find the accelaration of block A.
Answer» Given the set up shown in the figure. Blocks $A, B$ and $C$ have masses $m_{A} = M$ & $m_{B} = m_{C} = m$ . The strings are assumed massless and unstretchable and the pulley is frictionless. There is no friction between block $B$ and the support table, but there is friction between blocks $B$ and $C$ donated by a given coefficient $μ$ . Find the accelaration of block $A$ .

Discussion

45.	89. Three particles of mass 'm' are placed fixed at the corners of an equilateral triangle of length 'R\sqrt{}3'. What is the value of escape speed of any mass from the centroid of the triangle?
Answer» 89. Three particles of mass 'm' are placed fixed at the corners of an equilateral triangle of length 'R\sqrt{}3'. What is the value of escape speed of any mass from the centroid of the triangle?

Discussion

46.	State Fleming’s Left-hand rule.
Answer» State Fleming’s Left-hand rule.

Discussion

47.	30. A capacitor as shown in figure has square plates length l each and are inlclined at angle theta with one another.for small value of theta,capacitance is.given by.
Answer» 30. A capacitor as shown in figure has square plates length l each and are inlclined at angle theta with one another.for small value of theta,capacitance is.given by.

Discussion

48.	118.A particle is projected at an angle theta with horizontal from ground the slope of the trajectory of the particle varies with time as
Answer» 118.A particle is projected at an angle theta with horizontal from ground the slope of the trajectory of the particle varies with time as

Discussion

49.	Four charges Q, q, Q and q are kept at the four corners of a square. What is the relation between Q and q so that the net force on a charge q is zero?
Answer» Four charges Q, q, Q and q are kept at the four corners of a square. What is the relation between Q and q so that the net force on a charge q is zero?

Discussion

50.	A charged particle enters a uniform magnetic field with velocity that makes an angle of 45∘ with the magnetic field. The pitch of the helical path followed by the particle is p. The radius of the helix is
Answer» A charged particle enters a uniform magnetic field with velocity that makes an angle of $45^{\circ}$ with the magnetic field. The pitch of the helical path followed by the particle is $p .$ The radius of the helix is

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

If two conducting spheres are separately charged and then brought in contact, then

A glass prism of refractive index 1.5 is immersed in water (refractive index 4/3). A light beam incident normally on the face AB is totally reflected to reach the face BC if

The position vectors of the points A,B and C are respectively →a,→b and →c. If P divides −−→AB in the ratio 3:4 and Q divides −−→BC in the ratio 2:1 both externally, then −−→PQ is

A circular track of radius 600 m is to be designed for cars at an average speed of 180 km/hr. What should be the angle of banking of the track?

A thin uniform circular ring is rolling down an inclined plane of inclination 30∘ without slipping. Its linear acceleration along the inclined plane will be

An electric dipole of dipole moment p is lying along uniform electric field E.work done in rotating the dipole by 90 degree is

Disc of radius a2 is cut out from a disc of radius a. Find x co-ordinate of centre of mass from origin.

44. find the moment of inertia of pair of spheres, each having a mass m and radius r kept in contact about tangent passing through the point of contact

Aparallel beam of light of wavelength 500 nm falls on a narrow slitand the resulting diffraction pattern is observed on a screen 1 maway. It is observed that the first minimum is at a distance of 2.5mm from the centre of the screen. Find the width of the slit.

Q 35/180 Ajuggler is throwing ball vertically up in airat regular time interval of 1 second. Sixth ball justleaves the hand, when first ball comes back to hishands. Then minimum speed with which he throws theball is (g 10 m/s2)

A streetcar moves rectilinearly from station A to the next station B with an acceleration varying according to the law f=a−bx, where a and b are constant, and x is the distance from station A. The distance between the two stations and maximum velocity are

Find acceleration of block B if F=40 N.(Take g=10 m/s2)

Why diamagnetic and paramagnetic substances align themselves in external magnetic field perpendicular and parallel to field respectively?

A stone of mass 2 kg is tied to one end of a rope of length 2 m. The other end is fixed to a vertical axis, around which the mass is performing a circular motion with an angular speed of 2π rad/s. Then, tension in the rope (in newtons) will be:

A tangential force 10 N acts at the top of a thin spherical shell of mass 2 kg. Find the acceleration of the shell if it rolls without slipping.

A particle moves in a straight line, so that x =\sqrt t .Then its acceleration is proportional to6.(1) Velocity(2) (Velocity)3/2(3) (Velocity)3(4) (Velocity)2

The value of the integral ln5∫0ex√ex−1ex+3dx is

Two balls are thrown simul†an eously.A vertically upwards with a speed of 20m/s from the ground and B, vertically downwards from a height of 40m with the same speed and along the same line of motion. At what points do the two balls collide

49.A mirror forms a real image 3 cm high of object 1 cm high if the separation between the image and object is 30 cm find the nature and focal length of mirror used

If a particle has velocity v(t)=4t+2 m/s, the average speed in 2 sec is

A particle having mass 10 g oscillates according to the equation x=(2.0 cm) sin[100 s−1)t+π.6]. Find (a) the amplitude, the time period and the spring constant (b) the position, the velocity and the acceleration at t=0.

The spin angular momentum of an electron is given by:

An object thrown vertically upwards from the ground passes the height 5m twice in an interval of 10 sec .time of flight ?

If the centre of parallelopiped formed by −−→PA=2^i−^j+^k,−−→PB=−4^i+2^j−^k,−−→PC=−2^i−^j+2^k is given by position vector 3^i−2^j−2^k, then the position vector of point P is

In an AC circuit, the instantaneous EMF and current is given by E=100sin30t, i=20sin(30t−π4).In one cycle of AC, the average power consumed by the circuit and the wattles current are, respectively

A ball is dropped from height h.The total distance covered by the body in last second of its motion is equal to distance covered by it in the first three seconds ,what is the vslue of h.

A chain of mass m and length l is placed on a table with one-sixth of it hanging freely from the table edge. The amount of work done to pull the chain on to the table is

A sphere of iron and another of wood, both of same radius are placed on the surface of water. State which of the two will sink ? Give reason to your answer.

Escape velocity of an atmospheric particle which is 1000 km above the earth's surface, is (radius of earth is6400 km and g =9.8 m/s2)17(1) 6.5 km/s(2) 8 km/s(3) 10 km/s(4) 11.2 km/sTE

how to solve n^{th} second problems in horizontal motion when a body stops under cons†an t deceleration and then reverses its direction.

2. A particle of mass M rotates in a circle of radius a with uniform angular speed W. it is viewed from a frame rotating with a uniform angular speed W^°. the centrifugal force on the particle is:

What are the equations of trajectory motion?

Find the radius of gyration for a rectangular lamina having mass m about an axis passing through C.O.M and perpendicular to the plane of lamina. (Given: length, a=4 m; breadth, b=3 m)

A man wants to reach point B on the opposite bank of a river flowing at a speed u as shown in figure. what minimum speed relative to water should the man have so that he can reach point B?

Let u1 be the frequency of the series limit of the Lyman series, u2 be the frequency of the first line of the Lyman series, and u3 be the frequency of the series limit of the Balmer series. Then-

Two short electric dipoles at a certain distanceapply a force F on each other. If the separation is doubled, then the force of interaction between the dipoles, will become approximately

A string of length 1 m and mass 5 g is fixed at both ends. The tension in the string is 8.0 N. The string is set into vibration using an external vibrator of frequency 100 Hz. The separation between successive nodes on the string is close to:

The two ends of train moving with constant acceleration pass a certain point with velocities u and 3u the velocity with which middle point of the train passes the same point

89. Three particles of mass 'm' are placed fixed at the corners of an equilateral triangle of length 'R\sqrt{}3'. What is the value of escape speed of any mass from the centroid of the triangle?

State Fleming’s Left-hand rule.

30. A capacitor as shown in figure has square plates length l each and are inlclined at angle theta with one another.for small value of theta,capacitance is.given by.

118.A particle is projected at an angle theta with horizontal from ground the slope of the trajectory of the particle varies with time as

Four charges Q, q, Q and q are kept at the four corners of a square. What is the relation between Q and q so that the net force on a charge q is zero?

A charged particle enters a uniform magnetic field with velocity that makes an angle of 45∘ with the magnetic field. The pitch of the helical path followed by the particle is p. The radius of the helix is