50278 + Interview Questions in Physics

1.	A tank is filled with water and two holes A and B are made in it. For getting same range, ratio of h′h is
Answer» A tank is filled with water and two holes $A$ and $B$ are made in it. For getting same range, ratio of $\frac{h^{'}}{h}$ is

Discussion

2.	A body covers half its journey in 40m/s and the other half with a speed of 60m/s . What is the average speed during the whole journey?
Answer» A body covers half its journey in 40m/s and the other half with a speed of 60m/s . What is the average speed during the whole journey?

Discussion

3.	A particle starting from rest moves with constant tangential acceleration on a circular path of radius 10π m. After 2.5 rotation the velocity of the particle is 50 m/s, its tangential acceleration is
Answer» A particle starting from rest moves with constant tangential acceleration on a circular path of radius $\frac{10}{π} m$ . After $2.5$ rotation the velocity of the particle is $50 m/s$ , its tangential acceleration is

Discussion

4.	Two travelling waves y1=A sin [k(x - ct)] and y2=A sin [k(x+ct)] are superimposed on string. The distance between adjacent nodes is
Answer» Two travelling waves $y_{1} = A sin [k(x - ct)]$ and $y_{2} = A sin [k (x + c t)]$ are superimposed on string. The distance between adjacent nodes is

Discussion

5.	A particle starts its motion from point A in the positive x direction in such a way that after every t sec it is at a distance of t2 from the starting point. Find its instantaneous velocity at t=4th sec also the rate at which velocity changes.
Answer» A particle starts its motion from point A in the positive x direction in such a way that after every t sec it is at a distance of $t^{2}$ from the starting point. Find its instantaneous velocity at $t = 4^{t h}$ sec also the rate at which velocity changes.

Discussion

6.	If a trainA overtakes a train B speed of A wrt.B is the difference of their velocities but when A crosses B speed of A wrt. B is the sum of their velocities
Answer» If a trainA overtakes a train B speed of A wrt.B is the difference of their velocities but when A crosses B speed of A wrt. B is the sum of their velocities

Discussion

7.	An object at rest at point A slides down on a smooth surface ending at point B at a fixed hemisphere as shown in the figure. Determine the angle θ at which the object will leave the hemisphere.
Answer» An object at rest at point $A$ slides down on a smooth surface ending at point $B$ at a fixed hemisphere as shown in the figure. Determine the angle $θ$ at which the object will leave the hemisphere.

Discussion

8.	Two containers A and B contain the same ideal gas at the same temperature and pressure. If volume of container A is twice the volume of container B, then find the ratio of gas molecules present in container A to container B.
Answer» Two containers $A$ and $B$ contain the same ideal gas at the same temperature and pressure. If volume of container $A$ is twice the volume of container $B$ , then find the ratio of gas molecules present in container $A$ to container $B$ .

Discussion

9.	What is the relation between refractive indices μ,μ1 and μ2 if the behaviour of light rays is as shown in figure.
Answer» What is the relation between refractive indices $μ, μ_{1}$ and $μ_{2}$ if the behaviour of light rays is as shown in figure.

Discussion

10.	A balloon starts from the ground and moves vertically upwards with an acceleration of 2 m/s×s ,a stone is released from the balloon . find the time by the stone to reach the ground
Answer» A balloon starts from the ground and moves vertically upwards with an acceleration of 2 m/s×s ,a stone is released from the balloon . find the time by the stone to reach the ground

Discussion

11.	If 1 bacterium divides in 1 min and in 1 hr a cup is filled. At what time cup is half filled? ( please help i find these ques really confusing)
Answer» If 1 bacterium divides in 1 min and in 1 hr a cup is filled. At what time cup is half filled? ( please help i find these ques really confusing)

Discussion

12.	in case of tangential stress,the strain is given by the relative displacement between the top and the bottom phase .in that case the strain must be equal to costheta right
Answer» in case of tangential stress,the strain is given by the relative displacement between the top and the bottom phase .in that case the strain must be equal to costheta right

Discussion

13.	If the acceleration is increasing, will the velocity also increase in every case?
Answer» If the acceleration is increasing, will the velocity also increase in every case?

Discussion

14.	Two identical solid copper spheres of radius R are placed on contact with each other . The gravitational attraction between them is proportional to what? 1 ) R2 2)1 / R2 3) R 4 4)1/ R 4
Answer» Two identical solid copper spheres of radius R are placed on contact with each other . The gravitational attraction between them is proportional to what? 1 ) R²2)1 / R²3) R ⁴4)1/ R ⁴

Discussion

15.	How can we say that charge acquired by glass rod is positive while for ebonite rod it is negative?
Answer» How can we say that charge acquired by glass rod is positive while for ebonite rod it is negative?

Discussion

16.	A dip needle lies initially in the magnetic meridian when it shows an angle of dip q at a place. The dip circle is rotated through an angle x in the horizontal plane and then it shows an angle of dip θ′ . Then tan θ′tan θ is
Answer» A dip needle lies initially in the magnetic meridian when it shows an angle of dip q at a place. The dip circle is rotated through an angle x in the horizontal plane and then it shows an angle of dip $θ^{'}$ . Then $\frac{t a n θ^{'}}{t a n θ}$ is

Discussion

17.	Where will be the higher potential of a charged particle ,near to the electric field or far away distance from the election field of a constant particle kept at a point?
Answer» Where will be the higher potential of a charged particle ,near to the electric field or far away distance from the election field of a constant particle kept at a point?

Discussion

18.	When we slap someone lets say, our hand gets really close to the face which will result in electomagnetic relulsion. Is this repulsion really stong because if it is then that would imply that we actually never touch anything because of repulsion?
Answer» When we slap someone lets say, our hand gets really close to the face which will result in electomagnetic relulsion. Is this repulsion really stong because if it is then that would imply that we actually never touch anything because of repulsion?

Discussion

19.	Calculate Reynold's number if a fluid having a viscosity of 0.25 N.s/m2 and density of 800 kg/m3 flows through a pipe of radius 10 mm with a velocity of 2 m/s.
Answer» Calculate Reynold's number if a fluid having a viscosity of $0.25 {N.s/m}^{2}$ and density of $800 {kg/m}^{3}$ flows through a pipe of radius $10 mm$ with a velocity of $2 m/s$ .

Discussion

20.	A cube of aluminium of sides 0.1 m is subjected to a shearing force of 100 N. The top face of the cube is displaced through 0.02 cm with respect to the bottom face. The shearing strain would be
Answer» A cube of aluminium of sides 0.1 m is subjected to a shearing force of 100 N. The top face of the cube is displaced through 0.02 cm with respect to the bottom face. The shearing strain would be

Discussion

21.	Calculate the shortest wavelength of the spectral lines emitted in Balmer series.[Given Rydberg constant, R=107m−l]
Answer» Calculate the shortest wavelength of the spectral lines emitted in Balmer series.[Given Rydberg constant, R= $10^{7} m^{- l}$ ]

Discussion

22.	The plate resistance and the amplification factor of a triode are 10KΩ and 20. The tube is operated at plate voltage 250 V and grid voltage -7.5 V. The plate current is 10 mA. (a) To what value should the grid voltage be changed so as to increase the plate current to 15 mA? (b) To what value should the plate votage be changed to take the plate current back to 10 mA?
Answer» The plate resistance and the amplification factor of a triode are $10 K Ω$ and 20. The tube is operated at plate voltage 250 V and grid voltage -7.5 V. The plate current is 10 mA. (a) To what value should the grid voltage be changed so as to increase the plate current to 15 mA? (b) To what value should the plate votage be changed to take the plate current back to 10 mA?

Discussion

23.	A solid sphere of mass 2 kg is resting inside a cube as shown in the figure. The cube is moving with a velocity v=(5t^i+2t^j)m/s. Here t is the time in second. All surface are smooth. The sphere is at rest with respect to the cube. What is the total force exerted by the sphere on the cube. (Take g=10 m/s2)
Answer» A solid sphere of mass 2 kg is resting inside a cube as shown in the figure. The cube is moving with a velocity $v = (5 t^i + 2 t^j) m / s$ . Here t is the time in second. All surface are smooth. The sphere is at rest with respect to the cube. What is the total force exerted by the sphere on the cube. (Take $g = 10 m / s^{2}$ )

Discussion

24.	Show that there can be no net charge in a region in which the electric field uniform at all points.
Answer» Show that there can be no net charge in a region in which the electric field uniform at all points.

Discussion

25.	Three rods of identical cross-sectional area are made from the same metal from the sides of an isosceles right angled triangle ABC, right angled at B. The points A and B are maintained at temperatures T and √2T respectively. In the steady state, the temperature of point C is TC. There is a point D on BA, whose temperature is same as TC. Then the ratio BDDA is found to be 1√x. Here x is
Answer» Three rods of identical cross-sectional area are made from the same metal from the sides of an isosceles right angled triangle ABC, right angled at B. The points A and B are maintained at temperatures $T$ and $\sqrt{2} T$ respectively. In the steady state, the temperature of point C is $T_{C}$ . There is a point D on BA, whose temperature is same as $T_{C}$ . Then the ratio $\frac{B D}{D A}$ is found to be $\frac{1}{\sqrt{x}}$ . Here $x$ is

Discussion

26.	A small block oscillates back and forth on a smooth concave surface of radius R (figure 12-E17). Find the time period of small oscillation.
Answer» A small block oscillates back and forth on a smooth concave surface of radius R (figure 12-E17). Find the time period of small oscillation.

26.

A small block oscillates back and forth on a smooth concave surface of radius R (figure 12-E17). Find the time period of small oscillation.

Answer»

A small block oscillates back and forth on a smooth concave surface of radius R (figure 12-E17). Find the time period of small oscillation.

Discussion

27.	If a capillary tube is dipped into liquid and the level of the liquid inside and outside are same, then the angle of contact is
Answer» If a capillary tube is dipped into liquid and the level of the liquid inside and outside are same, then the angle of contact is

Discussion

28.	A 100 pF capacitor is charged to a potential difference of 24 V. It is connected to an uncharged capacitor of capacitance 20 pF. What will be the new potential difference across the 100 pF capacitor ?
Answer» A 100 pF capacitor is charged to a potential difference of 24 V. It is connected to an uncharged capacitor of capacitance 20 pF. What will be the new potential difference across the 100 pF capacitor ?

Discussion

29.	Binding energy per nucleon vs mass number curve for nuclei is shown in the figure. W, X, Y and Z are four nuclei indicated on the curve. The process that would release energy is
Answer» Binding energy per nucleon vs mass number curve for nuclei is shown in the figure. W, X, Y and Z are four nuclei indicated on the curve. The process that would release energy is

Discussion

30.	On a winter day, the outside temperature is 00 C and relative humidity 40 %. The air from outside comes into a room and is heated to 200 C. What is the relative humidity in the room ? The saturation vapour pressure at 00 C is 4.6 mm of mercury and at 200 C it is 18 mm of mercury.
Answer» On a winter day, the outside temperature is $0^{0}$ C and relative humidity 40 %. The air from outside comes into a room and is heated to $20^{0}$ C. What is the relative humidity in the room ? The saturation vapour pressure at $0^{0}$ C is 4.6 mm of mercury and at $20^{0}$ C it is 18 mm of mercury.

Discussion

31.	Calculate the pay load when a balloon of radius 10 m, mass 100 kg is filled with helium at 1.66 bar at 27°C. (Density air=1.2 kg m-3 and R=0.083 bar dm3 K-1 mol-1)
Answer» Calculate the pay load when a balloon of radius 10 m, mass 100 kg is filled with helium at 1.66 bar at 27°C. (Density air=1.2 kg m^-3and R=0.083 bar dm³K^-1mol^-1)

Discussion

32.	A particle (a mud pallet) of mass 'm' strikes a smooth stationary wedge of mass M with a velocity v0, at an angle θ with horizontal. If the collision is perfectly inelastic, find the velocity of the wedge just after the collision.
Answer» A particle (a mud pallet) of mass 'm' strikes a smooth stationary wedge of mass $M$ with a velocity $v_{0}$ , at an angle $θ$ with horizontal. If the collision is perfectly inelastic, find the velocity of the wedge just after the collision.

32.

A particle (a mud pallet) of mass 'm' strikes a smooth stationary wedge of mass M with a velocity v0, at an angle θ with horizontal. If the collision is perfectly inelastic, find the velocity of the wedge just after the collision.

Answer»

A particle (a mud pallet) of mass 'm' strikes a smooth stationary wedge of mass $M$ with a velocity $v_{0}$ , at an angle $θ$ with horizontal. If the collision is perfectly inelastic, find the velocity of the wedge just after the collision.

Discussion

33.	The gravitational potential due to a mass distribution is V=A√x2+a2. The gravitational field due to the mass distribution is
Answer» The gravitational potential due to a mass distribution is $V = \frac{A}{\sqrt{x^{2} + a^{2}}}$ . The gravitational field due to the mass distribution is

Discussion

34.	A stone is dropped from a height of 100m on earth. At the same time, another stone is thrown vertically upwards from a ground with a velocity of 50msec. At what height from the ground will the stone meet?
Answer» A stone is dropped from a height of 100m on earth. At the same time, another stone is thrown vertically upwards from a ground with a velocity of 50 $\frac{m}{s e c}$ . At what height from the ground will the stone meet?

Discussion

35.	The second overtone of an open organ pipe has the same frequency as the first overtone of a closed pipe L metre long. The length of the open pipe will be
Answer» The second overtone of an open organ pipe has the same frequency as the first overtone of a closed pipe $L$ metre long. The length of the open pipe will be

Discussion

36.	At what temperature will the speed of sound in hydrogen be the same as in oxygen at 100∘ C? Molar masses of oxygen and hydrogen are in the ratio 16:1.
Answer» At what temperature will the speed of sound in hydrogen be the same as in oxygen at 100 $^{\circ}$ C? Molar masses of oxygen and hydrogen are in the ratio 16:1.

Discussion

37.	A uniformly charged conducting sphere of 2.4 m diameter has a surface charge density of 80.0 μC/m2. Find the charge on the sphere. What is the total electric flux leaving the surface of the sphere?
Answer» A uniformly charged conducting sphere of 2.4 m diameter has a surface charge density of 80.0 $μ C / m^{2}$ . Find the charge on the sphere. What is the total electric flux leaving the surface of the sphere?

37.

A uniformly charged conducting sphere of 2.4 m diameter has a surface charge density of 80.0 μC/m2. Find the charge on the sphere. What is the total electric flux leaving the surface of the sphere?

Answer»

A uniformly charged conducting sphere of 2.4 m diameter has a
surface charge density of 80.0 $μ C / m^{2}$ .
Find the charge on the sphere.

What is the total electric flux leaving the surface of the
sphere?

Discussion

38.	If W1,W2 and W3 represent the work done in moving a particle from A to B along three different paths 1, 2 and 3 respectively (as shown) in the gravitational field of a point mass m, find the correct relation
Answer» If $W_{1}, W_{2} a n d W_{3}$ represent the work done in moving a particle from A to B along three different paths 1, 2 and 3 respectively (as shown) in the gravitational field of a point mass m, find the correct relation

38.

If W1,W2 and W3 represent the work done in moving a particle from A to B along three different paths 1, 2 and 3 respectively (as shown) in the gravitational field of a point mass m, find the correct relation

Answer»

If $W_{1}, W_{2} a n d W_{3}$ represent the work done in moving a particle from A to B along three different paths 1, 2 and 3 respectively (as shown) in the gravitational field of a point mass m, find the correct relation

Discussion

39.	A capacitor consists of two stationary parallel plates shaped as a semi-circular disc of radius R and a movable plate made of dielectric with relative permittivity, K = 10 and capable of rotating about an axis O between the stationary plates. The thickness of the movable plate is equal to d which is practically the separation between the stationary plates. A potential difference V=√(4dϵ0R2) is applied to the capacitor. Find the magnitude of the moment of forces relative to the axis O acting on the movable plate in the position shown in figure.___
Answer» A capacitor consists of two stationary parallel plates shaped as a semi-circular disc of radius R and a movable plate made of dielectric with relative permittivity, K = 10 and capable of rotating about an axis O between the stationary plates. The thickness of the movable plate is equal to d which is practically the separation between the stationary plates. A potential difference $V = \sqrt{(\frac{4 d}{ϵ_{0} R^{2}})}$ is applied to the capacitor. Find the magnitude of the moment of forces relative to the axis O acting on the movable plate in the position shown in figure.___

39.

A capacitor consists of two stationary parallel plates shaped as a semi-circular disc of radius R and a movable plate made of dielectric with relative permittivity, K = 10 and capable of rotating about an axis O between the stationary plates. The thickness of the movable plate is equal to d which is practically the separation between the stationary plates. A potential difference V=√(4dϵ0R2) is applied to the capacitor. Find the magnitude of the moment of forces relative to the axis O acting on the movable plate in the position shown in figure.___

Answer»

A capacitor consists of two stationary parallel plates shaped as a semi-circular disc of radius R and a movable plate made of dielectric with relative permittivity, K = 10 and capable of rotating about an axis O between the stationary plates. The thickness of the movable plate is equal to d which is practically the separation between the stationary plates. A potential difference $V = \sqrt{(\frac{4 d}{ϵ_{0} R^{2}})}$ is applied to the capacitor. Find the magnitude of the moment of forces relative to the axis O acting on the movable plate in the position shown in figure.___

Discussion

40.	Current sensitivity of a moving coil galvanometer is 5divA and its voltage sensitivity (angular deflection per unit voltage applied) is 20×10−3divvolt−1 The resistance of the galvanometer is
Answer» Current sensitivity of a moving coil galvanometer is $\frac{5 d i v}{A}$ and its voltage sensitivity (angular deflection per unit voltage applied) is $20 {\times 10}^{- 3} d i v v o l t^{- 1}$ The resistance of the galvanometer is

40.

Current sensitivity of a moving coil galvanometer is 5divA and its voltage sensitivity (angular deflection per unit voltage applied) is 20×10−3divvolt−1 The resistance of the galvanometer is

Answer»

Current sensitivity of a moving coil galvanometer is $\frac{5 d i v}{A}$ and its voltage sensitivity (angular deflection per unit voltage applied) is $20 {\times 10}^{- 3} d i v v o l t^{- 1}$ The resistance of the galvanometer is

Discussion

41.	The length and breadth of a field are measured l=(120±2)m and b=(100±5)m respectively. What is the area of the field?
Answer» The length and breadth of a field are measured $l = (120 \pm 2) m$ and $b = (100 \pm 5) m$ respectively. What is the area of the field?

Discussion

42.	When an object is placed in front of a concave mirror of focal length f, a virtual image is produced with a magnification of 2. To obtain a real image with a magnification of 2, the object has to be moved by a distance equal to
Answer» When an object is placed in front of a concave mirror of focal length f, a virtual image is produced with a magnification of 2. To obtain a real image with a magnification of 2, the object has to be moved by a distance equal to

Discussion

43.	A ball of mass 2 kg hanging from a spring oscillates with a time period 2π seconds. Ball is removed when it is in equilibrium position, then spring shortens by
Answer» A ball of mass 2 kg hanging from a spring oscillates with a time period $2 π$ seconds. Ball is removed when it is in equilibrium position, then spring shortens by

Discussion

44.	Two blocks of masses M and 2M are connected to a light spring constant k. That has one end fixed as shown in the figure. The horizontal surface and pulley are frictionless. The blocks are released from rest when the spring is in its relaxed state.
Answer» Two blocks of masses M and 2M are connected to a light spring constant k. That has one end fixed as shown in the figure. The horizontal surface and pulley are frictionless. The blocks are released from rest when the spring is in its relaxed state.

44.

Two blocks of masses M and 2M are connected to a light spring constant k. That has one end fixed as shown in the figure. The horizontal surface and pulley are frictionless. The blocks are released from rest when the spring is in its relaxed state.

Answer»

Two blocks of masses M and 2M are connected to a light spring constant k. That has one end fixed as shown in the figure. The horizontal surface and pulley are frictionless. The blocks are released from rest when the spring is in its relaxed state.

Discussion

45.	A small piece of wire is passed through the gap between the poles of a magnet in 0.1 sec. An emf of 4×10−3V is induced in the wire. The magnetic flux between the poles in wb is
Answer» A small piece of wire is passed through the gap between the poles of a magnet in 0.1 sec. An emf of $4 \times 10^{- 3} V$ is induced in the wire. The magnetic flux between the poles in wb is

Discussion

46.	A bob of mass m is suspended by a massless string of length I. The horizontal velocity v at position A is just sufficient to make it reach the point B. The angle θ at which the speed of the bob is half of that at A, satisfies
Answer» A bob of mass m is suspended by a massless string of length I. The horizontal velocity v at position A is just sufficient to make it reach the point B. The angle $θ$ at which the speed of the bob is half of that at A, satisfies

Discussion

47.	The temperatures of two outer surfaces of a composite slab, consisting of two materials having coefficients of thermal conductivities K and 2K and thicknesses, x and 4x respectively are T2 and T1 with T2>T1 . The rate of heat transfer through the slab, in a steady state is kA(T2−T1)xα What is the value of α ?
Answer» The temperatures of two outer surfaces of a composite slab, consisting of two materials having coefficients of thermal conductivities K and 2K and thicknesses, x and 4x respectively are $T_{2} a n d T_{1} w i t h T_{2} > T_{1}$ . The rate of heat transfer through the slab, in a steady state is $\frac{k A (T_{2} - T_{1})}{x} α$ What is the value of $α$ ?

Discussion

48.	A cell sends a current i1 through a coil of resistance R1 and a current i2 through a coil of resistance is R2. The emf of the cell is
Answer» A cell sends a current $i_{1}$ through a coil of resistance $R_{1}$ and a current $i_{2}$ through a coil of resistance is $R_{2}$ . The emf of the cell is

Discussion

49.	An object of mass m is tied to a string of length l and a variable force Fis applied on it which brings the string gradually to an angle with the vertical. The work done by the force F is
Answer» An object of mass m is tied to a string of length l and a variable force Fis applied on it which brings the string gradually to an angle with the vertical. The work done by the force F is

49.

An object of mass m is tied to a string of length l and a variable force Fis applied on it which brings the string gradually to an angle with the vertical. The work done by the force F is

Answer»

An object of mass m is tied to a string of length l and a variable force Fis applied on it which brings the string gradually to an angle with the vertical. The work done by the force F is

Discussion

50.	In the secondary circuit of a potentiometer a cell of internal resistance 1.5 gives balancing length of 52 cm. To get a balancing length of 40 cm, how much resistance is to be connected across the cell?
Answer» In the secondary circuit of a potentiometer a cell of internal resistance 1.5 gives balancing length of 52 cm. To get a balancing length of 40 cm, how much resistance is to be connected across the cell?

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

A tank is filled with water and two holes A and B are made in it. For getting same range, ratio of h′h is

A body covers half its journey in 40m/s and the other half with a speed of 60m/s . What is the average speed during the whole journey?

A particle starting from rest moves with constant tangential acceleration on a circular path of radius 10π m. After 2.5 rotation the velocity of the particle is 50 m/s, its tangential acceleration is

Two travelling waves y1=A sin [k(x - ct)] and y2=A sin [k(x+ct)] are superimposed on string. The distance between adjacent nodes is

A particle starts its motion from point A in the positive x direction in such a way that after every t sec it is at a distance of t2 from the starting point. Find its instantaneous velocity at t=4th sec also the rate at which velocity changes.

If a trainA overtakes a train B speed of A wrt.B is the difference of their velocities but when A crosses B speed of A wrt. B is the sum of their velocities

An object at rest at point A slides down on a smooth surface ending at point B at a fixed hemisphere as shown in the figure. Determine the angle θ at which the object will leave the hemisphere.

Two containers A and B contain the same ideal gas at the same temperature and pressure. If volume of container A is twice the volume of container B, then find the ratio of gas molecules present in container A to container B.

What is the relation between refractive indices μ,μ1 and μ2 if the behaviour of light rays is as shown in figure.

A balloon starts from the ground and moves vertically upwards with an acceleration of 2 m/s×s ,a stone is released from the balloon . find the time by the stone to reach the ground

If 1 bacterium divides in 1 min and in 1 hr a cup is filled. At what time cup is half filled? ( please help i find these ques really confusing)

in case of tangential stress,the strain is given by the relative displacement between the top and the bottom phase .in that case the strain must be equal to costheta right

If the acceleration is increasing, will the velocity also increase in every case?

Two identical solid copper spheres of radius R are placed on contact with each other . The gravitational attraction between them is proportional to what? 1 ) R2 2)1 / R2 3) R 4 4)1/ R 4

How can we say that charge acquired by glass rod is positive while for ebonite rod it is negative?

A dip needle lies initially in the magnetic meridian when it shows an angle of dip q at a place. The dip circle is rotated through an angle x in the horizontal plane and then it shows an angle of dip ​θ′ . Then tan θ′tan θ is

Where will be the higher potential of a charged particle ,near to the electric field or far away distance from the election field of a constant particle kept at a point?

When we slap someone lets say, our hand gets really close to the face which will result in electomagnetic relulsion. Is this repulsion really stong because if it is then that would imply that we actually never touch anything because of repulsion?

Calculate Reynold's number if a fluid having a viscosity of 0.25 N.s/m2 and density of 800 kg/m3 flows through a pipe of radius 10 mm with a velocity of 2 m/s.

A cube of aluminium of sides 0.1 m is subjected to a shearing force of 100 N. The top face of the cube is displaced through 0.02 cm with respect to the bottom face. The shearing strain would be

Calculate the shortest wavelength of the spectral lines emitted in Balmer series.[Given Rydberg constant, R=107m−l]

Show that there can be no net charge in a region in which the electric field uniform at all points.

A small block oscillates back and forth on a smooth concave surface of radius R (figure 12-E17). Find the time period of small oscillation.

If a capillary tube is dipped into liquid and the level of the liquid inside and outside are same, then the angle of contact is

A 100 pF capacitor is charged to a potential difference of 24 V. It is connected to an uncharged capacitor of capacitance 20 pF. What will be the new potential difference across the 100 pF capacitor ?

Binding energy per nucleon vs mass number curve for nuclei is shown in the figure. W, X, Y and Z are four nuclei indicated on the curve. The process that would release energy is

On a winter day, the outside temperature is 00 C and relative humidity 40 %. The air from outside comes into a room and is heated to 200 C. What is the relative humidity in the room ? The saturation vapour pressure at 00 C is 4.6 mm of mercury and at 200 C it is 18 mm of mercury.

Calculate the pay load when a balloon of radius 10 m, mass 100 kg is filled with helium at 1.66 bar at 27°C. (Density air=1.2 kg m-3 and R=0.083 bar dm3 K-1 mol-1)

A particle (a mud pallet) of mass 'm' strikes a smooth stationary wedge of mass M with a velocity v0, at an angle θ with horizontal. If the collision is perfectly inelastic, find the velocity of the wedge just after the collision.

The gravitational potential due to a mass distribution is V=A√x2+a2. The gravitational field due to the mass distribution is

A stone is dropped from a height of 100m on earth. At the same time, another stone is thrown vertically upwards from a ground with a velocity of 50msec. At what height from the ground will the stone meet?

The second overtone of an open organ pipe has the same frequency as the first overtone of a closed pipe L metre long. The length of the open pipe will be

At what temperature will the speed of sound in hydrogen be the same as in oxygen at 100∘ C? Molar masses of oxygen and hydrogen are in the ratio 16:1.

A uniformly charged conducting sphere of 2.4 m diameter has a surface charge density of 80.0 μC/m2. Find the charge on the sphere. What is the total electric flux leaving the surface of the sphere?

If W1,W2 and W3 represent the work done in moving a particle from A to B along three different paths 1, 2 and 3 respectively (as shown) in the gravitational field of a point mass m, find the correct relation

Current sensitivity of a moving coil galvanometer is 5divA and its voltage sensitivity (angular deflection per unit voltage applied) is 20×10−3divvolt−1 The resistance of the galvanometer is

The length and breadth of a field are measured l=(120±2)m and b=(100±5)m respectively. What is the area of the field?

When an object is placed in front of a concave mirror of focal length f, a virtual image is produced with a magnification of 2. To obtain a real image with a magnification of 2, the object has to be moved by a distance equal to

A ball of mass 2 kg hanging from a spring oscillates with a time period 2π seconds. Ball is removed when it is in equilibrium position, then spring shortens by

Two blocks of masses M and 2M are connected to a light spring constant k. That has one end fixed as shown in the figure. The horizontal surface and pulley are frictionless. The blocks are released from rest when the spring is in its relaxed state.

A small piece of wire is passed through the gap between the poles of a magnet in 0.1 sec. An emf of 4×10−3V is induced in the wire. The magnetic flux between the poles in wb is

A bob of mass m is suspended by a massless string of length I. The horizontal velocity v at position A is just sufficient to make it reach the point B. The angle θ at which the speed of the bob is half of that at A, satisfies

A cell sends a current i1 through a coil of resistance R1 and a current i2 through a coil of resistance is R2. The emf of the cell is

An object of mass m is tied to a string of length l and a variable force Fis applied on it which brings the string gradually to an angle with the vertical. The work done by the force F is

In the secondary circuit of a potentiometer a cell of internal resistance 1.5 gives balancing length of 52 cm. To get a balancing length of 40 cm, how much resistance is to be connected across the cell?

A dip needle lies initially in the magnetic meridian when it shows an angle of dip q at a place. The dip circle is rotated through an angle x in the horizontal plane and then it shows an angle of dip θ′ . Then tan θ′tan θ is