50278 + Interview Questions in Physics

1.	A drunkard is walking along a straight road.He takes 5 steps forward and 3steps backward followed again by 5 step forward and 3step backward and so on.Each step is 1m and takes 1s .There is a pit on the road 11m away from starting point.The drunkard will fall into the pit after.....ANS:29s(pls give explanation becoz I have already gone through the solution but not able to follow some steps especially why they calculate the time for 6m)
Answer» A drunkard is walking along a straight road.He takes 5 steps forward and 3steps backward followed again by 5 step forward and 3step backward and so on.Each step is 1m and takes 1s .There is a pit on the road 11m away from starting point.The drunkard will fall into the pit after.....ANS:29s(pls give explanation becoz I have already gone through the solution but not able to follow some steps especially why they calculate the time for 6m)

Discussion

2.	Area of a parallelogram, whose diagonals are 3^i+^j−2^k and ^i−3^j+4^k will be:
Answer» Area of a parallelogram, whose diagonals are $3^i +^j - 2^k a n d^i - 3^j + 4^k$ will be:

Discussion

3.	Explain torque.
Answer» Explain torque.

Discussion

4.	A rocket is fired with a velocity 0.6 times the escape velocity on the surface of the earth.How high will it go from the surface.
Answer» A rocket is fired with a velocity 0.6 times the escape velocity on the surface of the earth.How high will it go from the surface.

Discussion

5.	Two conducting spheres of radii R1 and R2 are kept widely separated from each other. What are their individual capacitances ? If the spheres are connected by a metal wire, what will be the capacitance of the combination ? Think in terms of series-parallel connections.
Answer» Two conducting spheres of radii $R_{1}$ and $R_{2}$ are kept widely separated from each other. What are their individual capacitances ? If the spheres are connected by a metal wire, what will be the capacitance of the combination ? Think in terms of series-parallel connections.

Discussion

6.	Are null point and balance point are same or different things for meter bridge if not how they can be defined ?
Answer» Are null point and balance point are same or different things for meter bridge if not how they can be defined ?

Discussion

7.	540 calories of heat convert 1 cc of water at 100∘C to 1670 cc steam at 100∘C at a pressure of 1 atm. Then the work done against the atmospheric pressure is nearly (Take atmospheric pressure, P=1.01×106 dyne/cm2)
Answer» $540$ calories of heat convert $1 cc$ of water at $100^{\circ} C$ to $1670 cc$ steam at $100^{\circ} C$ at a pressure of $1 atm$ . Then the work done against the atmospheric pressure is nearly (Take atmospheric pressure, $P = 1.01 \times 10^{6} {dyne/cm}^{2}$ )

Discussion

8.	If charge flown through a wire is given by q=3sin(3t), then find out the current flown through the wire at t=π9 seconds.
Answer» If charge flown through a wire is given by $q = 3 sin (3 t)$ , then find out the current flown through the wire at $t = \frac{π}{9}$ seconds.

Discussion

9.	For this lens;
Answer» For this lens;

Discussion

10.	Six particles situvated at the corners of a regular hexagon of side a move at a constant speed v. Each particle maintains a direction towards the particle at the next corner. Calculate the time the particle will take to meet each other.
Answer» Six particles situvated at the corners of a regular hexagon of side a move at a constant speed v. Each particle maintains a direction towards the particle at the next corner. Calculate the time the particle will take to meet each other.

Discussion

11.	A travelling wave is produced on a long horizontal string by vibrating an end up and down sinusoidally. The amplitude of vibration is 1.0 cm and the displacement becomes zero 200 times per second. The linear mass density of the string is 0.10 kg m−1 and it is kept under a tension of 90 N. (a) Find the speed and the wavelength of the wave. (b) Assume that the wave moves in the positive x-direction and at t = 0, the end x = 0 is at its positive extreme position. Write the wave equation. (c) Find the velocity and acceleration of the particle at x = 50 cm at time t = 10 ms.
Answer» A travelling wave is produced on a long horizontal string by vibrating an end up and down sinusoidally. The amplitude of vibration is 1.0 cm and the displacement becomes zero 200 times per second. The linear mass density of the string is $0.10 k g m^{- 1}$ and it is kept under a tension of 90 N. (a) Find the speed and the wavelength of the wave. (b) Assume that the wave moves in the positive x-direction and at t = 0, the end x = 0 is at its positive extreme position. Write the wave equation. (c) Find the velocity and acceleration of the particle at x = 50 cm at time t = 10 ms.

Discussion

12.	How to interpret work done by a force in a given power vv s time graph?
Answer» How to interpret work done by a force in a given power vv s time graph?

12.

How to interpret work done by a force in a given power vv s time graph?

Answer»

How to interpret work done by a force in a given power vv

s time graph?

Discussion

13.	Which among the following gates has output = A . B ?
Answer» Which among the following gates has output = A . B ?

Discussion

14.	neglect the effect of rotation of earthsuppose the earth suddenly stops attracting the objects placed near its surfacea person standing on the surface of the earth will 1)fly up 2)slip along the surface 3)fly around the tangent to the Earth surface 4)remain standing Please provide the reason...
Answer» neglect the effect of rotation of earthsuppose the earth suddenly stops attracting the objects placed near its surfacea person standing on the surface of the earth will 1)fly up 2)slip along the surface 3)fly around the tangent to the Earth surface 4)remain standing Please provide the reason...

Discussion

15.	If there is a lone charge in the universe, and it moves a certain distance, what is the change in its electrical potential energy?
Answer» If there is a lone charge in the universe, and it moves a certain distance, what is the change in its electrical potential energy?

Discussion

16.	A ball is dropped from a height of 45 m from the ground. The coefficient of restitution beween the ball and the ground is 23. What is the distance in m travelled by the ball in 4th second of its motion? Assume negligible time is spent in rebounding. Let g=10 m/s2.
Answer» A ball is dropped from a height of $45 m$ from the ground. The coefficient of restitution beween the ball and the ground is $\frac{2}{3}$ . What is the distance in m travelled by the ball in 4th second of its motion? Assume negligible time is spent in rebounding. Let $g = 10 m / s^{2} .$

Discussion

17.	If a planet exists whose mass and radius were half that of earth,the acceleration due to gravity at its surface would be:
Answer» If a planet exists whose mass and radius were half that of earth,the acceleration due to gravity at its surface would be:

Discussion

18.	An α−particle experiences the following force due to a nucleus (k>0) →F=kr2ifr>R=−KR3→rifr<R The correct potential energy diagram for the above force is
Answer» An $α -$ particle experiences the following force due to a nucleus $(k > 0)$ $\begin{matrix} \to F = \frac{k}{r^{2}} & i f & r > R = \frac{- K}{R^{3}} \to r & i f & r < R \end{matrix}$ The correct potential energy diagram for the above force is

18.

An α−particle experiences the following force due to a nucleus (k>0) →F=kr2ifr>R=−KR3→rifr<R The correct potential energy diagram for the above force is

Answer»

An $α -$ particle experiences the following force due to a nucleus $(k > 0)$
$\begin{matrix} \to F = \frac{k}{r^{2}} & i f & r > R = \frac{- K}{R^{3}} \to r & i f & r < R \end{matrix}$

The correct potential energy diagram for the above force is

Discussion

19.	Two thin symmetrical lenses of different nature have equal radii of curvature of all faces R = 20 cm. The lenses are put close together and immersed in water. The focal length of the system is 24 cm. The difference between refractive indices of the lenses is (5n). Find n. The refractive index of water is 43. ___
Answer» Two thin symmetrical lenses of different nature have equal radii of curvature of all faces R = 20 cm. The lenses are put close together and immersed in water. The focal length of the system is 24 cm. The difference between refractive indices of the lenses is $(\frac{5}{n})$ . Find n. The refractive index of water is $\frac{4}{3}$ . ___

Discussion

20.	Force versus displacement curve is shown in the diagram. Find the final velocity of the particle of mass 5 kg at the end of 30 m, if it is moving initially with 2 m/s.
Answer» Force versus displacement curve is shown in the diagram. Find the final velocity of the particle of mass $5 kg$ at the end of $30 m$ , if it is moving initially with $2 m/s$ .

Discussion

21.	If pressure amplitude of a sound wave in a medium is tripled and the wavelength is doubled then amplitude of displacement of the particles in the medium becomes x times of initial value. The value of x is
Answer» If pressure amplitude of a sound wave in a medium is tripled and the wavelength is doubled then amplitude of displacement of the particles in the medium becomes $x$ times of initial value. The value of $x$ is

Discussion

22.	A flatcar of mass m0=20 kg is moving to the right due to a constant horizontal force F=10 N. Sand spills on the flatcar from a stationary hopper. The velocity of loading is constant and equal to μ=1 kg/s. Find the time dependence of the velocity of the flatcar in the process of loading. The friction is negligibly small.
Answer» A flatcar of mass $m_{0} = 20 kg$ is moving to the right due to a constant horizontal force $F = 10 N$ . Sand spills on the flatcar from a stationary hopper. The velocity of loading is constant and equal to $μ = 1 kg/s$ . Find the time dependence of the velocity of the flatcar in the process of loading. The friction is negligibly small.

Discussion

23.	A force →F=(5^i+3^j+2^k) N is applied over a particle which displaces it to a point having position vector→r=(2^i−^j) m from origin. The work done on the particle (in J) is
Answer» A force $\to F = (5^i + 3^j + 2^k) N$ is applied over a particle which displaces it to a point having position vector $\to r = (2^i -^j) m$ from origin. The work done on the particle (in $J$ ) is

Discussion

24.	An electron carries a charge of magnitude .
Answer» An electron carries a charge of magnitude .

Discussion

25.	An object is displaced from position vector →r1=(2^i+3^j) m to →r2=(4^i+6^j) m under a force F=(3x2^i+2y^j) N. Find the work done in joules by this force.
Answer» An object is displaced from position vector $_{1} = (2^i + 3^j) m$ to $_{2} = (4^i + 6^j) m$ under a force $F = (3 x^{2}^i + 2 y^j) N$ . Find the work done in joules by this force.

Discussion

26.	A box of volume 22.4L filled with helium at STP, will have NA=6.023×1023 atoms. Let us look at a much simpler, unrealistic sample of gas where we just have five atoms, having the following velocity components along a fixed direction: 1337.2 m/s,1399.6 m/s,1362.4m/s and1382.1m/s. Calculate the rms speed along the given direction, and the average kinetic energy of each molecule. The mass of a helium atom is 6.646×10−27kg.
Answer» A box of volume 22.4L filled with helium at STP, will have $N_{A} = 6.023 \times 10^{23}$ atoms. Let us look at a much simpler, unrealistic sample of gas where we just have five atoms, having the following velocity components along a fixed direction: 1337.2 m/s,1399.6 m/s,1362.4m/s and1382.1m/s. Calculate the rms speed along the given direction, and the average kinetic energy of each molecule. The mass of a helium atom is $6.646 \times 10^{- 27} k g$ .

Discussion

27.	In a young’s double slit experiment the resultant intensity at a point on the screen with two sources with intensities 2I and 8I is 14I. Calculate the phase difference between the two sources.
Answer» In a young’s double slit experiment the resultant intensity at a point on the screen with two sources with intensities 2I and 8I is 14I. Calculate the phase difference between the two sources.

Discussion

28.	The potential difference(in Volts) between points A and B, in a section of a circuit shown, is
Answer» The potential difference(in Volts) between points A and B, in a section of a circuit shown, is

Discussion

29.	In sports, the timing of a 200 m straight dash is recorded at the finish point on hearing the sound of a gun fired at the starting point. The time recorded will be more accurate
Answer» In sports, the timing of a 200 m straight dash is recorded at the finish point on hearing the sound of a gun fired at the starting point. The time recorded will be more accurate

Discussion

30.	A light rod of length 1 m is pivoted at its centre and two masses of 5 kg and 2 kg are hung from the ends as shown in the figure. Find the initial angular acceleration of the rod assuming that it was horizontal in the beginning.
Answer» A light rod of length 1 m is pivoted at its centre and two masses of 5 kg and 2 kg are hung from the ends as shown in the figure. Find the initial angular acceleration of the rod assuming that it was horizontal in the beginning.

Discussion

31.	The magnetic field B inside a long solenoid, carrying a current of 5.00 A, is 3.14×10−2 T. Find the number of turns per unit length of the solenoid.
Answer» The magnetic field B inside a long solenoid, carrying a current of 5.00 A, is $3.14 \times 10^{- 2} T .$ Find the number of turns per unit length of the solenoid.

Discussion

32.	(a) Write the principle of working of a metre bridge. (b) In a metre bridge, the balance point is found at a distance l1 with resistance R and S as shown in the figure. An unknown resistance X is now connected in parallel to the resistance S and the balance point is found at a distance l2. Obtain a formula for X in terms of l1,l2 and S.
Answer» (a) Write the principle of working of a metre bridge. (b) In a metre bridge, the balance point is found at a distance $l_{1}$ with resistance R and S as shown in the figure. An unknown resistance X is now connected in parallel to the resistance S and the balance point is found at a distance $l_{2}$ . Obtain a formula for X in terms of $l_{1}, l_{2}$ and S.

Discussion

33.	A uniform disc of mass m and radius r is suspended through a wire attached to its centre. If the time period of the torsional oscillations be T, what is the torsional constant of the wire ?
Answer» A uniform disc of mass m and radius r is suspended through a wire attached to its centre. If the time period of the torsional oscillations be T, what is the torsional constant of the wire ?

Discussion

34.	A balloon starts rising upwards with constant acceleration 15 m/s2 and after 10 s, a packet is dropped from it. The packet reaches the ground after t0 sec. Determine the value of t0 (in sec). Take g=10 m/s2 and √15=3.87.
Answer» A balloon starts rising upwards with constant acceleration $15 {m/s}^{2}$ and after $10 s$ , a packet is dropped from it. The packet reaches the ground after $t_{0} sec$ . Determine the value of $t_{0}$ (in sec). Take $g = 10 {m/s}^{2}$ and $\sqrt{15} = 3.87$ .

Discussion

35.	A sinusoidal voltage of peak value 200 volt is connected to a diode and resistor R in the circuit shown so that half wave rectification occurs. If the forward resistance of the diode is negligible compared to R the rms voltage (in volt) across R is approximately
Answer» A sinusoidal voltage of peak value 200 volt is connected to a diode and resistor R in the circuit shown so that half wave rectification occurs. If the forward resistance of the diode is negligible compared to R the rms voltage (in volt) across R is approximately

Discussion

36.	Two blocks A and B of same mass m connected by a light spring are suspended by an inextensible string as shown in the figure. Find the magnitude of the acceleration of block A and B just after the string is cut.
Answer» Two blocks $A$ and $B$ of same mass $m$ connected by a light spring are suspended by an inextensible string as shown in the figure. Find the magnitude of the acceleration of block $A$ and $B$ just after the string is cut.

Discussion

37.	A cobalt (atomic no. =27) target is bombarded with electrons, and the wavelengths of its characteristic X−ray spectrum are measured. A second weak characteristic spectrum is also found, due to an impurity in the target. The wavelengths of the Kα lines are 225.0 pm (cobalt) and 100.0 pm (impurity). Atomic number of the impurity is (take b=1)
Answer» A cobalt (atomic no. $= 27$ ) target is bombarded with electrons, and the wavelengths of its characteristic $X -$ ray spectrum are measured. A second weak characteristic spectrum is also found, due to an impurity in the target. The wavelengths of the $K_{α}$ lines are $225.0 pm$ (cobalt) and $100.0 pm$ (impurity). Atomic number of the impurity is (take $b = 1$ )

Discussion

38.	Two cylinders contain same amount of ideal monatomic gas. Same amount of heat is given to two cylinders. if temperature rise in cylinder A is To then temperature rise in cylinder B will be
Answer» Two cylinders contain same amount of ideal monatomic gas. Same amount of heat is given to two cylinders. if temperature rise in cylinder A is $T_{o}$ then temperature rise in cylinder B will be

Discussion

39.	The displacement -time graphs for two sound waves A and B are shown in the figure. The ratio of their intensities IAIB is equal to
Answer» The displacement -time graphs for two sound waves $A$ and $B$ are shown in the figure. The ratio of their intensities $\frac{I_{A}}{I_{B}}$ is equal to

Discussion

40.	The mass of the moon is about 12% of the earth. Compared to the gravitational force the earth exerts on the moon, the gravitational force the moon exerts on earth
Answer» The mass of the moon is about $\frac{1}{2} %$ of the earth. Compared to the gravitational force the earth exerts on the moon, the gravitational force the moon exerts on earth

Discussion

41.	A solid disc of mass M is just held in air horizontal by throwing 40 stones per sec vertically upwards to strike the disc each with a velocity 6 ms_1. If the mass of each stone is 0.05 kg. What is the mass of the disc? (g=10 ms_2)
Answer» A solid disc of mass M is just held in air horizontal by throwing 40 stones per sec vertically upwards to strike the disc each with a velocity 6 ms^_1. If the mass of each stone is 0.05 kg. What is the mass of the disc? (g=10 ms^_2)

Discussion

42.	If momentum (P), area (A) and time (T) are taken to be fundamental quantities, then energy has the Dimensional formula
Answer» If momentum (P), area (A) and time (T) are taken to be fundamental quantities, then energy has the Dimensional formula

Discussion

43.	A sound wave is traveling along positive x-direction. Displacement(s) of particles from their mean position at any time t is shown in the figure. Choose the correct alternative(s):
Answer» A sound wave is traveling along positive x-direction. Displacement(s) of particles from their mean position at any time t is shown in the figure. Choose the correct alternative(s):

43.

A sound wave is traveling along positive x-direction. Displacement(s) of particles from their mean position at any time t is shown in the figure. Choose the correct alternative(s):

Answer»

A sound wave is traveling along positive x-direction. Displacement(s) of particles from their mean position at any time t is shown in the figure. Choose the correct alternative(s):

Discussion

44.	An organ pipe of length L is open at one end and closed at the other. What are the wavelengths corresponding to the three lowest frequencies that can be produced with this pipe?
Answer» An organ pipe of length $L$ is open at one end and closed at the other. What are the wavelengths corresponding to the three lowest frequencies that can be produced with this pipe?

Discussion

45.	Two balls A and B having masses 1 kg and 2 kg, moving with speeds 21 m/s and 4 m/s respectively in opposite directions, collide head on. After collision A moves with a speed of 1 m/s in the same direction, then the coefficient of restitution is
Answer» Two balls A and B having masses 1 kg and 2 kg, moving with speeds 21 m/s and 4 m/s respectively in opposite directions, collide head on. After collision A moves with a speed of 1 m/s in the same direction, then the coefficient of restitution is

Discussion

46.	An inductance of 100 mH and a resistor of 50 ohm are connected in series to an ac source of 230 V, 50 Hz. Calculate the impedance, effective current and phase angle.
Answer» An inductance of 100 mH and a resistor of 50 ohm are connected in series to an ac source of 230 V, 50 Hz. Calculate the impedance, effective current and phase angle.

Discussion

47.	A point moves in a straight line so that its displacement x at time t is given by equation x2=t2+1. Its acceleration is:
Answer» A point moves in a straight line so that its displacement $x$ at time $t$ is given by equation $x^{2} = t^{2} + 1$ . Its acceleration is:

Discussion

48.	A photosensitive metallic surface has work function hv0. If photons of energy 2hv0 fall on this surface the electrons come out with a maximum velocity of 4×106 m/s. When the photon energy is increases to 5hv0 then maximum velocity of photo electron will be
Answer» A photosensitive metallic surface has work function $h v_{0}$ . If photons of energy $2 h v_{0}$ fall on this surface the electrons come out with a maximum velocity of $4 \times 10^{6} m / s$ . When the photon energy is increases to $5 h v_{0}$ then maximum velocity of photo electron will be

Discussion

49.	Some people say that not to keep our head on north direction when sleeping? What is the science behind it?
Answer» Some people say that not to keep our head on north direction when sleeping? What is the science behind it?

Discussion

50.	A block is shot with an initial velocity of 5 m/s on a rough horizontal plane. Find the distance covered by the block till it comes to rest. Given coefficient of friction between the surfaces of contact is 0.1 and g=10 m/s2.
Answer» A block is shot with an initial velocity of $5 m / s$ on a rough horizontal plane. Find the distance covered by the block till it comes to rest. Given coefficient of friction between the surfaces of contact is $0.1 and g = 10 m / s^{2}$ .

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Area of a parallelogram, whose diagonals are 3^i+^j−2^k and ^i−3^j+4^k will be:

Explain torque.

A rocket is fired with a velocity 0.6 times the escape velocity on the surface of the earth.How high will it go from the surface.

Two conducting spheres of radii R1 and R2 are kept widely separated from each other. What are their individual capacitances ? If the spheres are connected by a metal wire, what will be the capacitance of the combination ? Think in terms of series-parallel connections.

Are null point and balance point are same or different things for meter bridge if not how they can be defined ?

540 calories of heat convert 1 cc of water at 100∘C to 1670 cc steam at 100∘C at a pressure of 1 atm. Then the work done against the atmospheric pressure is nearly (Take atmospheric pressure, P=1.01×106 dyne/cm2)

If charge flown through a wire is given by q=3sin(3t), then find out the current flown through the wire at t=π9 seconds.

For this lens;

Six particles situvated at the corners of a regular hexagon of side a move at a constant speed v. Each particle maintains a direction towards the particle at the next corner. Calculate the time the particle will take to meet each other.

How to interpret work done by a force in a given power vv s time graph?

Which among the following gates has output = A . B ?

neglect the effect of rotation of earthsuppose the earth suddenly stops attracting the objects placed near its surfacea person standing on the surface of the earth will 1)fly up 2)slip along the surface 3)fly around the tangent to the Earth surface 4)remain standing Please provide the reason...

If there is a lone charge in the universe, and it moves a certain distance, what is the change in its electrical potential energy?

A ball is dropped from a height of 45 m from the ground. The coefficient of restitution beween the ball and the ground is 23. What is the distance in m travelled by the ball in 4th second of its motion? Assume negligible time is spent in rebounding. Let g=10 m/s2.

If a planet exists whose mass and radius were half that of earth,the acceleration due to gravity at its surface would be:

An α−particle experiences the following force due to a nucleus (k&gt;0) →F=kr2ifr&gt;R=−KR3→rifr&lt;R The correct potential energy diagram for the above force is

Force versus displacement curve is shown in the diagram. Find the final velocity of the particle of mass 5 kg at the end of 30 m, if it is moving initially with 2 m/s.

If pressure amplitude of a sound wave in a medium is tripled and the wavelength is doubled then amplitude of displacement of the particles in the medium becomes x times of initial value. The value of x is

A force →F=(5^i+3^j+2^k) N is applied over a particle which displaces it to a point having position vector→r=(2^i−^j) m from origin. The work done on the particle (in J) is

An electron carries a charge of magnitude .

An object is displaced from position vector →r1=(2^i+3^j) m to →r2=(4^i+6^j) m under a force F=(3x2^i+2y^j) N. Find the work done in joules by this force.

In a young’s double slit experiment the resultant intensity at a point on the screen with two sources with intensities 2I and 8I is 14I. Calculate the phase difference between the two sources.

The potential difference(in Volts) between points A and B, in a section of a circuit shown, is

In sports, the timing of a 200 m straight dash is recorded at the finish point on hearing the sound of a gun fired at the starting point. The time recorded will be more accurate

A light rod of length 1 m is pivoted at its centre and two masses of 5 kg and 2 kg are hung from the ends as shown in the figure. Find the initial angular acceleration of the rod assuming that it was horizontal in the beginning.

The magnetic field B inside a long solenoid, carrying a current of 5.00 A, is 3.14×10−2 T. Find the number of turns per unit length of the solenoid.

A uniform disc of mass m and radius r is suspended through a wire attached to its centre. If the time period of the torsional oscillations be T, what is the torsional constant of the wire ?

A balloon starts rising upwards with constant acceleration 15 m/s2 and after 10 s, a packet is dropped from it. The packet reaches the ground after t0 sec. Determine the value of t0 (in sec). Take g=10 m/s2 and √15=3.87.

A sinusoidal voltage of peak value 200 volt is connected to a diode and resistor R in the circuit shown so that half wave rectification occurs. If the forward resistance of the diode is negligible compared to R the rms voltage (in volt) across R is approximately

Two blocks A and B of same mass m connected by a light spring are suspended by an inextensible string as shown in the figure. Find the magnitude of the acceleration of block A and B just after the string is cut.

Two cylinders contain same amount of ideal monatomic gas. Same amount of heat is given to two cylinders. if temperature rise in cylinder A is To then temperature rise in cylinder B will be

The displacement -time graphs for two sound waves A and B are shown in the figure. The ratio of their intensities IAIB is equal to

The mass of the moon is about 12% of the earth. Compared to the gravitational force the earth exerts on the moon, the gravitational force the moon exerts on earth

A solid disc of mass M is just held in air horizontal by throwing 40 stones per sec vertically upwards to strike the disc each with a velocity 6 ms_1. If the mass of each stone is 0.05 kg. What is the mass of the disc? (g=10 ms_2)

If momentum (P), area (A) and time (T) are taken to be fundamental quantities, then energy has the Dimensional formula

A sound wave is traveling along positive x-direction. Displacement(s) of particles from their mean position at any time t is shown in the figure. Choose the correct alternative(s):

An organ pipe of length L is open at one end and closed at the other. What are the wavelengths corresponding to the three lowest frequencies that can be produced with this pipe?

Two balls A and B having masses 1 kg and 2 kg, moving with speeds 21 m/s and 4 m/s respectively in opposite directions, collide head on. After collision A moves with a speed of 1 m/s in the same direction, then the coefficient of restitution is

An inductance of 100 mH and a resistor of 50 ohm are connected in series to an ac source of 230 V, 50 Hz. Calculate the impedance, effective current and phase angle.

A point moves in a straight line so that its displacement x at time t is given by equation x2=t2+1. Its acceleration is:

A photosensitive metallic surface has work function hv0. If photons of energy 2hv0 fall on this surface the electrons come out with a maximum velocity of 4×106 m/s. When the photon energy is increases to 5hv0 then maximum velocity of photo electron will be

Some people say that not to keep our head on north direction when sleeping? What is the science behind it?

A block is shot with an initial velocity of 5 m/s on a rough horizontal plane. Find the distance covered by the block till it comes to rest. Given coefficient of friction between the surfaces of contact is 0.1 and g=10 m/s2.

An α−particle experiences the following force due to a nucleus (k>0) →F=kr2ifr>R=−KR3→rifr<R The correct potential energy diagram for the above force is