50278 + Interview Questions in Physics

1.	A body of mass 0.1 kg, moving with a velocity of 10 m/s hits a horizontal spring (fixed at the one end) of force constant 1000 N/m and comes to rest after compressing the spring. The compression of the spring is,
Answer» A body of mass $0.1 kg$ , moving with a velocity of $10 m/s$ hits a horizontal spring (fixed at the one end) of force constant $1000 N/m$ and comes to rest after compressing the spring. The compression of the spring is,

Discussion

2.	A very long magnet of pole strength 16 Am is placed vertically with its one pole on the table. At what distance from the pole, there will be a neutral point on the table[Take BH=4×10−5 Wb m−2]
Answer» A very long magnet of pole strength $16 Am$ is placed vertically with its one pole on the table. At what distance from the pole, there will be a neutral point on the table [Take $B_{H} = 4 \times 10^{- 5} {Wb m}^{- 2}$ ]

Discussion

3.	A certain metallic surface is illuminated with monochromatic light of wavelength, λ. The stopping potential for photo-electric current for this light is 3V0. If the same surface is illuminated with light of wave length 2λ, the stopping potential is V0. The threshold wavelength for this surface for photo- electric effect is :
Answer» A certain metallic surface is illuminated with monochromatic light of wavelength, $λ$ . The stopping potential for photo-electric current for this light is $3 V_{0}$ . If the same surface is illuminated with light of wave length $2 λ$ , the stopping potential is $V_{0}$ . The threshold wavelength for this surface for photo- electric effect is :

Discussion

4.	two objects attract each other by a force F . what will happen if the mass of bo
Answer» two objects attract each other by a force F . what will happen if the mass of bo

Discussion

5.	The initial capacitance of a parallel plate capacitor is C0 and after introducing a conducting sheet of thickness d3, the capacitance becomes C. Then CC0 is
Answer» The initial capacitance of a parallel plate capacitor is $C_{0}$ and after introducing a conducting sheet of thickness $\frac{d}{3}$ , the capacitance becomes $C$ . Then $\frac{C}{C_{0}}$ is

Discussion

6.	what does \|dv/dt\| and d\|v\|/dt represent . Can these be equal.
Answer» what does \|dv/dt\| and d\|v\|/dt represent . Can these be equal.

Discussion

7.	Write the postulates of Dalton’s atomic theory.
Answer» Write the postulates of Dalton’s atomic theory.

7.

Write the postulates of Dalton’s atomic theory.

Answer»

Write the postulates of Dalton’s atomic theory.

Discussion

8.	The logic behind 'NOR' gate is that it gives
Answer» The logic behind 'NOR' gate is that it gives

Discussion

9.	Two concentric spherical conducting shells of radii R and 2R carry charges Q and 2Q respectively. Change in electric potential on the outer shell when both are connected by a conducting wire is
Answer» Two concentric spherical conducting shells of radii R and 2R carry charges Q and 2Q respectively. Change in electric potential on the outer shell when both are connected by a conducting wire is

9.

Two concentric spherical conducting shells of radii R and 2R carry charges Q and 2Q respectively. Change in electric potential on the outer shell when both are connected by a conducting wire is

Answer»

Two concentric spherical conducting shells of radii R and 2R carry charges Q and 2Q respectively. Change in electric potential on the outer shell when both are connected by a conducting wire is

Discussion

10.	A puck of mass 100 gm is tied to a string and allowed to revolve in a horizontal circle of radius 2 cm on a frictionless horizontal table as shown in the figure. Other end of the string passes through a small hole at the centre of the table and a load of mass 5 kg is tied to the string. The suspended load remains in equilibrium while the puck revolves on the table. If the tension in the string is x (N) and speed of the puck is y (cm/s), then find the values of x and y respectively. Take g=10 m/s2.
Answer» A puck of mass $100 gm$ is tied to a string and allowed to revolve in a horizontal circle of radius $2 cm$ on a frictionless horizontal table as shown in the figure. Other end of the string passes through a small hole at the centre of the table and a load of mass $5 kg$ is tied to the string. The suspended load remains in equilibrium while the puck revolves on the table. If the tension in the string is $x (N)$ and speed of the puck is $y (cm/s)$ , then find the values of $x$ and $y$ respectively. Take $g = 10 {m/s}^{2}$ .

Discussion

11.	An athlete running with constant speed, completes one round of a circular track of radius R in 40 seconds. What will be his angular displacement at the end of 20 seconds?
Answer» An athlete running with constant speed, completes one round of a circular track of radius $R$ in $40 seconds$ . What will be his angular displacement at the end of $20 seconds$ ?

Discussion

12.	Potential energy for a conservative force →F is given by U(x,y)=cos(x+y). Force acting on a particle at position given by coordinates (0,π4) is
Answer» Potential energy for a conservative force $\to F$ is given by $U (x, y) = cos (x + y)$ . Force acting on a particle at position given by coordinates $(0, \frac{π}{4})$ is

Discussion

13.	Calculate angle strain in cyclohexane. 44 minute Explain how to calculate angle straim
Answer» Calculate angle strain in cyclohexane. 44 minute Explain how to calculate angle straim

Discussion

14.	The focal length of the objective and eyepiece of a microscope are 2 cm and 5 cm respectively and the distance between them is 20 cm. Find the distance of object from the objective, when the final image seen by the eye is 25 cm from the eyepiece.
Answer» The focal length of the objective and eyepiece of a microscope are $2 cm$ and $5 cm$ respectively and the distance between them is $20 cm .$ Find the distance of object from the objective, when the final image seen by the eye is $25 cm$ from the eyepiece.

Discussion

15.	draw a graph between electric and dis†an ce for two positive charges placed at a dis†an ce
Answer» draw a graph between electric and dis†an ce for two positive charges placed at a dis†an ce

Discussion

16.	How to rationalise
Answer» How to rationalise

Discussion

17.	1.On a cubical block of mass 10 kg kept on a plane, two forces of 6 N and 8 N are applied inopposite directions. The acceleration of the block is(A) 0.8 m/s2(C) 0.6 m/s2(B)0.2 m/s2(D) 5 m/s2
Answer» 1.On a cubical block of mass 10 kg kept on a plane, two forces of 6 N and 8 N are applied inopposite directions. The acceleration of the block is(A) 0.8 m/s2(C) 0.6 m/s2(B)0.2 m/s2(D) 5 m/s2

Discussion

18.	The angular velocity of a cycle wheel is 10 rad/s.If the diameter of the wheel is 80cm, then speed of cycle in m/s id
Answer» The angular velocity of a cycle wheel is 10 rad/s.If the diameter of the wheel is 80cm, then speed of cycle in m/s id

Discussion

19.	A 1000 kg car carrying four 82 kg people travels over a "washboard” dirt road with corrugations 4.0 m apart. The car bounces with maximum amplitude when its speed is 16 km/h. when the car stops, and the people get out, by how much does the car body rise on its suspension?
Answer» A 1000 kg car carrying four 82 kg people travels over a "washboard” dirt road with corrugations 4.0 m apart. The car bounces with maximum amplitude when its speed is 16 km/h. when the car stops, and the people get out, by how much does the car body rise on its suspension?

Discussion

20.	40.When a particle is thrown upward . What will be the graph for displacement vs time and velocity vs time?
Answer» 40.When a particle is thrown upward . What will be the graph for displacement vs time and velocity vs time?

Discussion

21.	Define work. When is work said to be done by a force?
Answer» Define work. When is work said to be done by a force?

Discussion

22.	A rocket is launched vertical from the surface of the earth of radius R with initial speed v. If atmospheric resistance is neglected , then maximum height attained by the rocket is(1) h=R/ (2gR/v^2 -1)(2) h=R/ (2gR/v^2 +1)(3) h=R^2/ (2gR/v^2 -1)(4) h=R^2/ (2gR/v^2 +1)
Answer» A rocket is launched vertical from the surface of the earth of radius R with initial speed v. If atmospheric resistance is neglected , then maximum height attained by the rocket is (1) h=R/ (2gR/v^2 -1) (2) h=R/ (2gR/v^2 +1) (3) h=R^2/ (2gR/v^2 -1) (4) h=R^2/ (2gR/v^2 +1)

Discussion

23.	In which of the following cases, the rays after reflection from a concave mirror diverge:
Answer» In which of the following cases, the rays after reflection from a concave mirror diverge:

23.

In which of the following cases, the rays after reflection from a concave mirror diverge:

Answer»

In which of the following cases, the rays after reflection from a concave mirror diverge:

Discussion

24.	A square shaped hole of side l=a2 is carved out at a distance d=a2 from the centre ‘O’ of a uniform circular disk of radius a. If the distance of the centre of mass of the remaining portion from O is−aX, value of X (to the nearest integer) is
Answer» A square shaped hole of side $l = \frac{a}{2}$ is carved out at a distance $d = \frac{a}{2}$ from the centre ‘O’ of a uniform circular disk of radius $a$ . If the distance of the centre of mass of the remaining portion from O is $- \frac{a}{X}$ , value of $X$ (to the nearest integer) is

Discussion

25.	ntIn the circuit shown the cells A and B have negligible resistances .For Va =12V ,R1=500ohms and R =100ohms the galvanometer shows no deflection.The value of Vb is?n ntExplain in detailn
Answer» ntIn the circuit shown the cells A and B have negligible resistances .For Va =12V ,R1=500ohms and R =100ohms the galvanometer shows no deflection.The value of Vb is?n ntExplain in detailn

Discussion

26.	Find the derivative of x1+tanx.
Answer» Find the derivative of $\frac{x}{1 + tan x} .$

Discussion

27.	A man walk 50 toward east, then 40 m towards North and then 20 m towards west. The magnitudes of his displacement is
Answer» A man walk 50 toward east, then 40 m towards North and then 20 m towards west. The magnitudes of his displacement is

Discussion

28.	Find the volume of a cuboid with length 4 cm, breadth 3 cm and height 2 cm.
Answer» Find the volume of a cuboid with length 4 cm, breadth 3 cm and height 2 cm.

Discussion

29.	Consider two containers A and B containing gases at the same pressure, volume and temperature. The gas in container A is compressed to half of its original volume isothermally while the gas in container B is compressed to half of its original volume adiabatically. The ratio of final pressure of gas in B to that of gas in A is
Answer» Consider two containers A and B containing gases at the same pressure, volume and temperature. The gas in container A is compressed to half of its original volume isothermally while the gas in container B is compressed to half of its original volume adiabatically. The ratio of final pressure of gas in B to that of gas in A is

Discussion

30.	88.the radius of earth is 6400km. at what depth from surface of the earth is the time period of a simple pendulum is 1% more than that on the surface of earth?
Answer» 88.the radius of earth is 6400km. at what depth from surface of the earth is the time period of a simple pendulum is 1% more than that on the surface of earth?

Discussion

31.	The coefficient of performance of a refrigerator is 5 . If the temperarture inside freezer is −200C, the temperature of the surroundings to which it rejects heat is
Answer» The coefficient of performance of a refrigerator is $5$ . If the temperarture inside freezer is $- 20^{0}$ C, the temperature of the surroundings to which it rejects heat is

Discussion

32.	A 5cm thick ice block is there on the surface of water in a lake. The temperature of air is −10∘ C; how much time it will take to double the thickness of the block(L=80 cal/g,Kice=0.004 Erg/s−k,dice=0.92gcm−3)
Answer» A 5cm thick ice block is there on the surface of water in a lake. The temperature of air is $- 10^{\circ}$ C; how much time it will take to double the thickness of the block $(L = 80 c a l / g, K_{i c e} = 0.004 E r g / s - k, d_{i c e} = 0.92 g c m^{- 3})$

Discussion

33.	Water flows in a rectangular concrete channel and undergoes a hydraulic jump such that half of its mechanical energy gets dissipated. If the channel carries 10cumecs water energy at a depth of 0.6 m and the width of channel is 5 m, the Froude number after the jump is.0.2
Answer» Water flows in a rectangular concrete channel and undergoes a hydraulic jump such that half of its mechanical energy gets dissipated. If the channel carries 10cumecs water energy at a depth of 0.6 m and the width of channel is 5 m, the Froude number after the jump is. 0.2

Discussion

34.	For a gas RCv=0.67. This gas is made up of molecules which are
Answer» For a gas $\frac{R}{C_{v}} = 0.67$ . This gas is made up of molecules which are

Discussion

35.	A coil of resistance 40 Ω is connected across a 4.0 V battery 0.10 s after the batter is connected, the current in the coil is 63 mA. Find the inductance of the coil.
Answer» A coil of resistance $40 Ω$ is connected across a 4.0 V battery 0.10 s after the batter is connected, the current in the coil is 63 mA. Find the inductance of the coil.

Discussion

36.	A wire carrying a 10 A current is bent to pass through various sides of a cube of side 10 cm as shown in the figure. A magnetic field →B=(2^i−3^j+^k) T is present in the region. Find the net force on the loop shown.
Answer» A wire carrying a $10 A$ current is bent to pass through various sides of a cube of side $10 cm$ as shown in the figure. A magnetic field $\to B = (2^i - 3^j +^k) T$ is present in the region. Find the net force on the loop shown.

Discussion

37.	A block of mass 5kg is at rest on a rough inclined surface if angle of inclination is 60° then force applied by it on block is ?
Answer» A block of mass 5kg is at rest on a rough inclined surface if angle of inclination is 60° then force applied by it on block is ?

Discussion

38.	Why liquids and gases cannot propagate transverse waves?
Answer» Why liquids and gases cannot propagate transverse waves?

Discussion

39.	A block inclined at an angle of 30 degree and connected with a string and coefficient of friction is 0.7 then find the tension in the string
Answer» A block inclined at an angle of 30 degree and connected with a string and coefficient of friction is 0.7 then find the tension in the string

Discussion

40.	A smooth sphere of radius R is set into translatory motion in a straight line with a constant acceleration a=g m/s2. A particle kept on the top of the sphere is released from there at zero velocity with respect to the sphere. If the particle slides down, then the speed of the particle with respect to the sphere when θ=45∘ is :(Here g=10 m/s2 is acceleration due to gravity and Radius, R=0.8 m).
Answer» A smooth sphere of radius $R$ is set into translatory motion in a straight line with a constant acceleration $a = g {m/s}^{2}$ . A particle kept on the top of the sphere is released from there at zero velocity with respect to the sphere. If the particle slides down, then the speed of the particle with respect to the sphere when $θ = 45^{\circ}$ is :(Here $g = 10 {m/s}^{2}$ is acceleration due to gravity and Radius, $R = 0.8 m$ ).

Discussion

41.	A car is negotiating a curved road of radius R. The road is banked at an angle θ. The coefficient of friction between the tyres of the car and the road is μs (μs < tanθ). The minimum speed of the car on this road, so that it does not slip is(formula?)
Answer» A car is negotiating a curved road of radius R. The road is banked at an angle θ. The coefficient of friction between the tyres of the car and the road is μs (μs < tanθ). The minimum speed of the car on this road, so that it does not slip is(formula?)

Discussion

42.	How does Newton's Cradle work?
Answer» How does Newton's Cradle work?

Discussion

43.	the physical quantity y is given as y=tanx and error in measurement of angle x is 3.6°. if sinx=3/5, then the error in the determined value of y is
Answer» the physical quantity y is given as y=tanx and error in measurement of angle x is 3.6°. if sinx=3/5, then the error in the determined value of y is

Discussion

44.	Explain,"The centre of gravity of the floating body and the centre of buoyancy are in the same vertical line".
Answer» Explain,"The centre of gravity of the floating body and the centre of buoyancy are in the same vertical line".

Discussion

45.	115.A particle of mass m moving towards the east with speed v collides with another particle of same mass and same speed moving towards north. If the two particle stick to each other the new particle of mass 2m will have a speed of: a. v b. v/2 c. v/ root 2 d. v root 2
Answer» 115.A particle of mass m moving towards the east with speed v collides with another particle of same mass and same speed moving towards north. If the two particle stick to each other the new particle of mass 2m will have a speed of: a. v b. v/2 c. v/ root 2 d. v root 2

Discussion

46.	70.A man has fallen into a ditch of width d and two of his friends are slowly pulling him out using a light rope and two fixed pulleys. Show that the force ( assumed equal for both the friends) exerted by each friend on the road increases as the man moves up. Find the force when the man is at a depth h.
Answer» 70.A man has fallen into a ditch of width d and two of his friends are slowly pulling him out using a light rope and two fixed pulleys. Show that the force ( assumed equal for both the friends) exerted by each friend on the road increases as the man moves up. Find the force when the man is at a depth h.

Discussion

47.	A body of mass m is taken from earth surface to the height h equal to radius of earth. The increase in potential energy will be
Answer» A body of mass m is taken from earth surface to the height h equal to radius of earth. The increase in potential energy will be

Discussion

48.	A projectile is fired with a speed u at an angle θ with the horizontal. Its speed when its direction of motion makes an angle α with the horizontal is
Answer» A projectile is fired with a speed $u$ at an angle $θ$ with the horizontal. Its speed when its direction of motion makes an angle $α$ with the horizontal is

Discussion

49.	(a) A conductor A with a cavity as shown in Fig. 1.36(a) is given acharge Q. Show that the entire charge must appear on the outersurface of the conductor. (b) Another conductor B with charge q isinserted into the cavity keeping B insulated from A. Show that thetotal charge on the outside surface of A is Q + q [Fig. 1.36(b)]. (c) Asensitive instrument is to be shielded from the strong electrostaticfields in its environment. Suggest a possible way.
Answer» (a) A conductor A with a cavity as shown in Fig. 1.36(a) is given acharge Q. Show that the entire charge must appear on the outersurface of the conductor. (b) Another conductor B with charge q isinserted into the cavity keeping B insulated from A. Show that thetotal charge on the outside surface of A is Q + q [Fig. 1.36(b)]. (c) Asensitive instrument is to be shielded from the strong electrostaticfields in its environment. Suggest a possible way.

Discussion

50.	Figure shows the speed-time graph of a particle. Find the distance travelled in the time interval 0 to 40 s.
Answer» Figure shows the speed-time graph of a particle. Find the distance travelled in the time interval $0$ to $40 s$ .

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

A body of mass 0.1 kg, moving with a velocity of 10 m/s hits a horizontal spring (fixed at the one end) of force constant 1000 N/m and comes to rest after compressing the spring. The compression of the spring is,

A very long magnet of pole strength 16 Am is placed vertically with its one pole on the table. At what distance from the pole, there will be a neutral point on the table[Take BH=4×10−5 Wb m−2]

two objects attract each other by a force F . what will happen if the mass of bo

The initial capacitance of a parallel plate capacitor is C0 and after introducing a conducting sheet of thickness d3, the capacitance becomes C. Then CC0 is

what does |dv/dt| and d|v|/dt represent . Can these be equal.

Write the postulates of Dalton’s atomic theory.

The logic behind 'NOR' gate is that it gives

Two concentric spherical conducting shells of radii R and 2R carry charges Q and 2Q respectively. Change in electric potential on the outer shell when both are connected by a conducting wire is

An athlete running with constant speed, completes one round of a circular track of radius R in 40 seconds. What will be his angular displacement at the end of 20 seconds?

Potential energy for a conservative force →F is given by U(x,y)=cos(x+y). Force acting on a particle at position given by coordinates (0,π4) is

Calculate angle strain in cyclohexane. 44 minute Explain how to calculate angle straim

The focal length of the objective and eyepiece of a microscope are 2 cm and 5 cm respectively and the distance between them is 20 cm. Find the distance of object from the objective, when the final image seen by the eye is 25 cm from the eyepiece.

draw a graph between electric and dis†an ce for two positive charges placed at a dis†an ce

How to rationalise

1.On a cubical block of mass 10 kg kept on a plane, two forces of 6 N and 8 N are applied inopposite directions. The acceleration of the block is(A) 0.8 m/s2(C) 0.6 m/s2(B)0.2 m/s2(D) 5 m/s2

The angular velocity of a cycle wheel is 10 rad/s.If the diameter of the wheel is 80cm, then speed of cycle in m/s id

A 1000 kg car carrying four 82 kg people travels over a "washboard” dirt road with corrugations 4.0 m apart. The car bounces with maximum amplitude when its speed is 16 km/h. when the car stops, and the people get out, by how much does the car body rise on its suspension?

40.When a particle is thrown upward . What will be the graph for displacement vs time and velocity vs time?

Define work. When is work said to be done by a force?

A rocket is launched vertical from the surface of the earth of radius R with initial speed v. If atmospheric resistance is neglected , then maximum height attained by the rocket is(1) h=R/ (2gR/v^2 -1)(2) h=R/ (2gR/v^2 +1)(3) h=R^2/ (2gR/v^2 -1)(4) h=R^2/ (2gR/v^2 +1)

In which of the following cases, the rays after reflection from a concave mirror diverge:

A square shaped hole of side l=a2 is carved out at a distance d=a2 from the centre ‘O’ of a uniform circular disk of radius a. If the distance of the centre of mass of the remaining portion from O is−aX, value of X (to the nearest integer) is

ntIn the circuit shown the cells A and B have negligible resistances .For Va =12V ,R1=500ohms and R =100ohms the galvanometer shows no deflection.The value of Vb is?n ntExplain in detailn

Find the derivative of x1+tanx.

A man walk 50 toward east, then 40 m towards North and then 20 m towards west. The magnitudes of his displacement is

Find the volume of a cuboid with length 4 cm, breadth 3 cm and height 2 cm.

88.the radius of earth is 6400km. at what depth from surface of the earth is the time period of a simple pendulum is 1% more than that on the surface of earth?

The coefficient of performance of a refrigerator is 5 . If the temperarture inside freezer is −200C, the temperature of the surroundings to which it rejects heat is

A 5cm thick ice block is there on the surface of water in a lake. The temperature of air is −10∘ C; how much time it will take to double the thickness of the block(L=80 cal/g,Kice=0.004 Erg/s−k,dice=0.92gcm−3)

Water flows in a rectangular concrete channel and undergoes a hydraulic jump such that half of its mechanical energy gets dissipated. If the channel carries 10cumecs water energy at a depth of 0.6 m and the width of channel is 5 m, the Froude number after the jump is.0.2

For a gas RCv=0.67. This gas is made up of molecules which are

A coil of resistance 40 Ω is connected across a 4.0 V battery 0.10 s after the batter is connected, the current in the coil is 63 mA. Find the inductance of the coil.

A wire carrying a 10 A current is bent to pass through various sides of a cube of side 10 cm as shown in the figure. A magnetic field →B=(2^i−3^j+^k) T is present in the region. Find the net force on the loop shown.

A block of mass 5kg is at rest on a rough inclined surface if angle of inclination is 60° then force applied by it on block is ?

Why liquids and gases cannot propagate transverse waves?

A block inclined at an angle of 30 degree and connected with a string and coefficient of friction is 0.7 then find the tension in the string

A car is negotiating a curved road of radius R. The road is banked at an angle θ. The coefficient of friction between the tyres of the car and the road is μs (μs < tanθ). The minimum speed of the car on this road, so that it does not slip is(formula?)

How does Newton's Cradle work?

the physical quantity y is given as y=tanx and error in measurement of angle x is 3.6°. if sinx=3/5, then the error in the determined value of y is

Explain,"The centre of gravity of the floating body and the centre of buoyancy are in the same vertical line".

115.A particle of mass m moving towards the east with speed v collides with another particle of same mass and same speed moving towards north. If the two particle stick to each other the new particle of mass 2m will have a speed of: a. v b. v/2 c. v/ root 2 d. v root 2

A body of mass m is taken from earth surface to the height h equal to radius of earth. The increase in potential energy will be

A projectile is fired with a speed u at an angle θ with the horizontal. Its speed when its direction of motion makes an angle α with the horizontal is

Figure shows the speed-time graph of a particle. Find the distance travelled in the time interval 0 to 40 s.