50278 + Interview Questions in Physics

1.	Two objects A and B are thrown with the same velocity directly upwards. Suppose if mass of A is greater than B. If the air exerts a constant and equal force of resistance on both bodies . Which body will cover more height
Answer» Two objects A and B are thrown with the same velocity directly upwards. Suppose if mass of A is greater than B. If the air exerts a constant and equal force of resistance on both bodies . Which body will cover more height

Discussion

2.	how is the focal length of a spherical mirror affected when the wavelength of the light used is increased?
Answer» how is the focal length of a spherical mirror affected when the wavelength of the light used is increased?

Discussion

3.	Why doesnt fire or flame cast a shadow
Answer» Why doesnt fire or flame cast a shadow

Discussion

4.	What is stopping potential .pls describe with full details
Answer» What is stopping potential .pls describe with full details

Discussion

5.	If a particle is projected from A normal to the plane calculate (i) Time of flight? (ii) AB=?
Answer» If a particle is projected from A normal to the plane calculate (i) Time of flight? (ii) AB=?

5.

If a particle is projected from A normal to the plane calculate (i) Time of flight? (ii) AB=?

Answer»

If a particle is projected from A normal to the plane calculate

(i) Time of flight?

(ii) AB=?

Discussion

6.	Suppose you are told that the linear size of everything in the universe has been doubled overnight can you tell the statement by measuring sizes with a metre stick ? can you test it by using the fact that the speed of light is universal constant and has not changed ? what will happen if all the clocks in the universe also start running at half the speed ?
Answer» Suppose you are told that the linear size of everything in the universe has been doubled overnight can you tell the statement by measuring sizes with a metre stick ? can you test it by using the fact that the speed of light is universal constant and has not changed ? what will happen if all the clocks in the universe also start running at half the speed ?

Discussion

7.	a man is looking at a small object placed at a near point. Without altering the position of his eye or the object, he puts a simple microscope of magnifying power 5x before his eyes. The angular magnification achieved is a.) 5 b.) 2.5 c.) 1 d.) 0.2
Answer» a man is looking at a small object placed at a near point. Without altering the position of his eye or the object, he puts a simple microscope of magnifying power 5x before his eyes. The angular magnification achieved is a.) 5 b.) 2.5 c.) 1 d.) 0.2

Discussion

8.	A solenoid has a core of a material with relative permeability of 500. The windings of the solenoid are insulted from the core and carry a current of 2A. If the number of turns is 1000 per meter, then magnetisation is ??
Answer» A solenoid has a core of a material with relative permeability of 500. The windings of the solenoid are insulted from the core and carry a current of 2A. If the number of turns is 1000 per meter, then magnetisation is ??

Discussion

9.	A particle is projected with a velocity u, at an angle α with the horizontal. Time at which its vertical component of velocity becomes half of its net speed at the highest point will be
Answer» A particle is projected with a velocity $u$ , at an angle $α$ with the horizontal. Time at which its vertical component of velocity becomes half of its net speed at the highest point will be

Discussion

10.	On a stationary sail-boat, air is blown at the sails from a fan attached to the boat. The boat will
Answer» On a stationary sail-boat, air is blown at the sails from a fan attached to the boat. The boat will

Discussion

11.	A police car moving at 22 m/s, chases a motorcyclist. The police man sounds his horn at 176 Hz, while both of them move towards a stationary siren of frequency 165 Hz. Calculate the speed of the motorcycle, if it is given that he does not observe any beats.
Answer» A police car moving at 22 m/s, chases a motorcyclist. The police man sounds his horn at 176 Hz, while both of them move towards a stationary siren of frequency 165 Hz. Calculate the speed of the motorcycle, if it is given that he does not observe any beats.

11.

A police car moving at 22 m/s, chases a motorcyclist. The police man sounds his horn at 176 Hz, while both of them move towards a stationary siren of frequency 165 Hz. Calculate the speed of the motorcycle, if it is given that he does not observe any beats.

Answer»

A police car moving at 22 m/s, chases a motorcyclist. The police man sounds his horn at 176 Hz, while both of them move towards a stationary siren of frequency 165 Hz. Calculate the speed of the motorcycle, if it is given that he does not observe any beats.

Discussion

12.	A cube of ice is floating in water contained in a vessel. When the ice melts, the level of water in the vessel
Answer» A cube of ice is floating in water contained in a vessel. When the ice melts, the level of water in the vessel

Discussion

13.	In a heating experiment, it was noted that the temperature of liquid in a beaker rose at 4.0 K per minute just before it began to boil, and 40 minutes later, all the liquid had boiled away. For this liquid, what is the value of ratio specific heat capacityspecific latent heat of vapourisation (in SI units)?
Answer» In a heating experiment, it was noted that the temperature of liquid in a beaker rose at $4.0 K$ per minute just before it began to boil, and $40$ minutes later, all the liquid had boiled away. For this liquid, what is the value of ratio $\frac{specific heat capacity}{specific latent heat of vapourisation}$ (in SI units)?

Discussion

14.	In variable state, the rate of flow of heat is controlled by
Answer» In variable state, the rate of flow of heat is controlled by

Discussion

15.	The diagram below shows a circuit used in an experiment to determine the emf and internal resistance of the cell C. A graph was plotted of the potential difference V between the terminals of the cell against the current I, which was varied by adjusting the rheostat. The graph is shown on the right, x and y are the intercepts of the graph with the axes as shown. What is the internal resistance of the cell ?
Answer» The diagram below shows a circuit used in an experiment to determine the emf and internal resistance of the cell $C$ . A graph was plotted of the potential difference $V$ between the terminals of the cell against the current $I$ , which was varied by adjusting the rheostat. The graph is shown on the right, $x$ and $y$ are the intercepts of the graph with the axes as shown. What is the internal resistance of the cell ?

Discussion

16.	The motion of a particle executing S.H.M. is given by x = 0.01 sin 100 π ( t + 0.05) , where x is in metres and time is in seconds. The time period is
Answer» The motion of a particle executing S.H.M. is given by x = 0.01 sin 100 $π$ ( t + 0.05) , where x is in metres and time is in seconds. The time period is

Discussion

17.	A satellite is launched into a circular orbit of radius ‘R’ around earth while a second satellite is launched intoan orbit of radius 1.02 R. The percentage difference in the time periods of the two satellites is
Answer» A satellite is launched into a circular orbit of radius ‘R’ around earth while a second satellite is launched intoan orbit of radius 1.02 R. The percentage difference in the time periods of the two satellites is

Discussion

18.	Calculate the shortest wavelength in the Balmer series of hydrogen atom. In which region (infrared, visible, ultraviolet) of hydrogen spectrum does this wavelength lie?
Answer» Calculate the shortest wavelength in the Balmer series of hydrogen atom. In which region (infrared, visible, ultraviolet) of hydrogen spectrum does this wavelength lie?

Discussion

19.	If the momentum of a body is increased n times, its kinetic energy increases
Answer» If the momentum of a body is increased n times, its kinetic energy increases

Discussion

20.	At what temperature is the root mean square velocity of gaseous hydrogen molecules is equal to that of oxygen molecules at 47∘C
Answer» At what temperature is the root mean square velocity of gaseous hydrogen molecules is equal to that of oxygen molecules at $47^{\circ} C$

20.

At what temperature is the root mean square velocity of gaseous hydrogen molecules is equal to that of oxygen molecules at 47∘C

Answer»

At what temperature is the root mean square velocity of gaseous hydrogen molecules is equal to that of oxygen molecules at $47^{\circ} C$

Discussion

21.	Monochromatic light of wavelength of 600nm is used in a YDSE. One of the slits is covered by a transparent sheet of thickness 1.8×10−5m made of a material of refractive index 1.6. How many fringes will shift due to the introduction of the sheet?
Answer» Monochromatic light of wavelength of 600nm is used in a YDSE. One of the slits is covered by a transparent sheet of thickness $1.8 \times 10^{- 5} m$ made of a material of refractive index 1.6. How many fringes will shift due to the introduction of the sheet?

Discussion

22.	A weight lifter jerks 220 kg vertically through 1.5 m and holds still at that height for two minutes. What is the work done in lifting and in holding it still respectively
Answer» A weight lifter jerks 220 kg vertically through 1.5 m and holds still at that height for two minutes. What is the work done in lifting and in holding it still respectively

Discussion

23.	In figure m1=5 kg and F = 1N. Find the acceleration of either block. Describe the motion of m1 if the string breaks but F continues to act.
Answer» In figure $m_{1} = 5$ kg and F = 1N. Find the acceleration of either block. Describe the motion of $m_{1}$ if the string breaks but F continues to act.

23.

In figure m1=5 kg and F = 1N. Find the acceleration of either block. Describe the motion of m1 if the string breaks but F continues to act.

Answer»

In figure $m_{1} = 5$ kg and F = 1N. Find the acceleration of either block. Describe the motion of $m_{1}$ if the string breaks but F continues to act.

Discussion

24.	A conducting disc of radius r rotates with a small but constant angular velocity w about its axis. A uniform magnetic field B exists parallel to the axis of rotation. Find the motional emf between the centre and the periphery of the disc.
Answer» A conducting disc of radius r rotates with a small but constant angular velocity w about its axis. A uniform magnetic field B exists parallel to the axis of rotation. Find the motional emf between the centre and the periphery of the disc.

Discussion

25.	What were the observations that made us look for the existence of neutrons?
Answer» What were the observations that made us look for the existence of neutrons?

Discussion

26.	A bird is sitting on horizontal stretched telephone wires. If its weight is W then the additional tension produced by it in the wires for angle less than 300 will be
Answer» A bird is sitting on horizontal stretched telephone wires. If its weight is W then the additional tension produced by it in the wires for angle less than 30⁰ will be

Discussion

27.	Any radiation in the ultra violet region of Hydrogen spectrum is able to eject photoelectrons from a metal. Then the threshold frequency of the metal for a threshold λ=1R=911˙A,is nearly
Answer» Any radiation in the ultra violet region of Hydrogen spectrum is able to eject photoelectrons from a metal. Then the threshold frequency of the metal for a threshold $λ = \frac{1}{R} = 911 ˙ A$ ,is nearly

Discussion

28.	A particle is executing SHM along x axis given by x=Asinwt. The average velocity during the time interval t=0 to t=Tis
Answer» A particle is executing SHM along x axis given by x=Asinwt. The average velocity during the time interval t=0 to t=Tis

Discussion

29.	If keplers second law states that Line from the sun to planet sweeps equal areas in equal intervals of time. So, for that velocity of planet should vary with respect to it's position. Then, according to newton's first law of motion, increase in speed of a planet say earth, should give all of us a jerk at regular intervals?
Answer» If keplers second law states that Line from the sun to planet sweeps equal areas in equal intervals of time. So, for that velocity of planet should vary with respect to it's position. Then, according to newton's first law of motion, increase in speed of a planet say earth, should give all of us a jerk at regular intervals?

Discussion

30.	Two metal spheres of same material and radius 'r' are in contact with each other. The gravitational force of attraction between two spheres is given by (k is constant) A)F=kr4 B)=F=k/r2 C)F=k/4r2 D)F=kr2
Answer» Two metal spheres of same material and radius 'r' are in contact with each other. The gravitational force of attraction between two spheres is given by (k is constant) A)F=kr⁴ B)=F=k/r² C)F=k/4r² D)F=kr²

Discussion

31.	A truck is moving horizontally with velocity V. A ball is thrown vertically upward with velocity U at an angleθ to the horizontal from the truck relative to it. The horizontal range of the shell relative to the ground is
Answer» A truck is moving horizontally with velocity V. A ball is thrown vertically upward with velocity U at an angle $θ$ to the horizontal from the truck relative to it. The horizontal range of the shell relative to the ground is

Discussion

32.	Suppose the bob of the previous problem has a speed of 1.4 m/s when the string makes an angle of 0.20 radian with the vertical. Find the tension at this instant. You can use cosθ≈ 1−θ2/2 and sinθ≈θ for small θ.
Answer» Suppose the bob of the previous problem has a speed of 1.4 m/s when the string makes an angle of 0.20 radian with the vertical. Find the tension at this instant. You can use $c o s θ \approx 1 - θ^{2} / 2$ and $s i n θ \approx θ$ for small $θ .$

Discussion

33.	A block of mass m is pushed up a fixed inclined plane of angle 30∘ by a Force of 10 N. Find the work done by the Force in pushing the block up the incline by 10M.
Answer» A block of mass m is pushed up a fixed inclined plane of angle $30^{\circ}$ by a Force of $10 N$ . Find the work done by the Force in pushing the block up the incline by $10 M$ .

33.

A block of mass m is pushed up a fixed inclined plane of angle 30∘ by a Force of 10 N. Find the work done by the Force in pushing the block up the incline by 10M.

Answer»

A block of mass m is pushed up a fixed inclined plane of angle $30^{\circ}$ by a Force of $10 N$ . Find the work done by the Force in pushing the block up the incline by $10 M$ .

Discussion

34.	92×576÷2√1296+(?)3+√49
Answer» $92 \times 576 \div 2 \sqrt{1296} + (?)^{3} + \sqrt{49}$

Discussion

35.	The uncertainty in the momentum of an electron is 1.0×10−5 kg ms−. The uncertainty in the position will be
Answer» The uncertainty in the momentum of an electron is $1.0 \times 10^{- 5}$ kg $m s^{-}$ . The uncertainty in the position will be

Discussion

36.	A man of mass M having a bag of mass m slips from the roof of a tall building of height H and starts falling vertically below figure.When at a height h from the ground,he notices that the ground below him is pretty hard,but there is a pond at a horizontal distance x from the line of fall.In order to save himself he throws the bag horizontally (with respect to himself) in the direction opposite to the pond.Calculate the minimum horizontal; velocity imparted to the bag so that the man lands in the water.If the man just succeeds to avoid the hard ground,where will the bag land?
Answer» A man of mass M having a bag of mass m slips from the roof of a tall building of height H and starts falling vertically below figure.When at a height h from the ground,he notices that the ground below him is pretty hard,but there is a pond at a horizontal distance x from the line of fall.In order to save himself he throws the bag horizontally (with respect to himself) in the direction opposite to the pond.Calculate the minimum horizontal; velocity imparted to the bag so that the man lands in the water.If the man just succeeds to avoid the hard ground,where will the bag land?

36.

A man of mass M having a bag of mass m slips from the roof of a tall building of height H and starts falling vertically below figure.When at a height h from the ground,he notices that the ground below him is pretty hard,but there is a pond at a horizontal distance x from the line of fall.In order to save himself he throws the bag horizontally (with respect to himself) in the direction opposite to the pond.Calculate the minimum horizontal; velocity imparted to the bag so that the man lands in the water.If the man just succeeds to avoid the hard ground,where will the bag land?

Answer»

A man of mass M having a bag of mass m slips from the roof of a tall building of height H and starts falling vertically below figure.When at a height h from the ground,he notices that the ground below him is pretty hard,but there is a pond at a horizontal distance x from the line of fall.In order to save himself he throws the bag horizontally (with respect to himself) in the direction opposite to the pond.Calculate the minimum horizontal; velocity imparted to the bag so that the man lands in the water.If the man just succeeds to avoid the hard ground,where will the bag land?

Discussion

37.	An iceberg is floating in an ocean. What fraction of its volume is above the water? (Given: density of ice=900 kg/m3 and density of ocean water =1030 kg/m3)
Answer» An iceberg is floating in an ocean. What fraction of its volume is above the water? (Given: density of ice $= 900 {kg/m}^{3}$ and density of ocean water $= 1030 {kg/m}^{3}$ )

Discussion

38.	Calculate the stress in a tight wire of a material whose young’s modulus is 19.6×1011 dyne/cm2, so that the speed of the longitudinal wave is 20 times the speed of transverse wave.
Answer» Calculate the stress in a tight wire of a material whose young’s modulus is $19.6 \times 10^{11} d y n e / c m^{2}$ , so that the speed of the longitudinal wave is 20 times the speed of transverse wave.

Discussion

39.	Sound with intensity larger than 120 dB appears painful to a person. A small speaker delivers 2.0 W of audio output. How close can the person get to the speaker without hurting his ears?
Answer» Sound with intensity larger than 120 dB appears painful to a person. A small speaker delivers 2.0 W of audio output. How close can the person get to the speaker without hurting his ears?

Discussion

40.	A body traveling along a straight line traversed one third of the total distance with a velocity 4 m/s. The remaining part of the distance was covered with a velocity 2 m/s for half of the time and with velocity 4 m/s for the other half of time. The mean velocity averaged over the whole time of motion is
Answer» A body traveling along a straight line traversed one third of the total distance with a velocity 4 m/s. The remaining part of the distance was covered with a velocity 2 m/s for half of the time and with velocity 4 m/s for the other half of time. The mean velocity averaged over the whole time of motion is

Discussion

41.	A plane electromagnetic wave Ez=100cos(6×108t+4x)V/m propagates in a medium of refractive index
Answer» A plane electromagnetic wave $E z = 100 c o s (6 \times 10^{8} t + 4 x) V / m$ propagates in a medium of refractive index

41.

A plane electromagnetic wave Ez=100cos(6×108t+4x)V/m propagates in a medium of refractive index

Answer»

A plane electromagnetic wave

$E z = 100 c o s (6 \times 10^{8} t + 4 x) V / m$ propagates in a medium of refractive index

Discussion

42.	Two radio stations broadcast their programmes at the same amplitude A and at slightly different frequencies ω1 and ω2 respectively where ω1–ω2=1 kHz. A detector receives the signals from the two stations simultaneously. It can only detect signals of Intensity >2A2. Find the interval between successive maxima of the intensity of the signal received by the detector.
Answer» Two radio stations broadcast their programmes at the same amplitude $A$ and at slightly different frequencies $ω_{1}$ and $ω_{2}$ respectively where $ω_{1} - ω_{2} = 1 kHz$ . A detector receives the signals from the two stations simultaneously. It can only detect signals of Intensity $> 2 A^{2}$ . Find the interval between successive maxima of the intensity of the signal received by the detector.

Discussion

43.	Choose the Most appropriate answer. In a tube when a sound wave is created, compression and rarefaction pulses are produced. The rarefaction pulse has pressure.
Answer» Choose the Most appropriate answer. In a tube when a sound wave is created, compression and rarefaction pulses are produced. The rarefaction pulse has pressure.

Discussion

44.	A box, when hung from a spring balance shows a reading of 50 kg. If the same box is hung from the same spring balance inside an evacuated chamber, the reading on the scale will be
Answer» A box, when hung from a spring balance shows a reading of 50 kg. If the same box is hung from the same spring balance inside an evacuated chamber, the reading on the scale will be

Discussion

45.	A body covers the first 1/3 of the distance with a velocity of 2 m/s, the next 1/3 with 3 m/s and the rest of the distance with 6 m/s. The average velocity in m/s for covering the whole distance is (assume that the body travels with constant velocity in all the parts in a straight line)
Answer» A body covers the first $1 / 3$ of the distance with a velocity of $2 m/s$ , the next $1 / 3$ with $3 m/s$ and the rest of the distance with $6 m/s$ . The average velocity in $m/s$ for covering the whole distance is (assume that the body travels with constant velocity in all the parts in a straight line)

Discussion

46.	A body is projected with initial velocity of (8^i+6^j) m/s from origin, find angular velocity of body wrt to an axis passing through origin and perpendicular to the x -y plane when it lands. (Here ^i,^j are unit vectors corresponding to X, Y axis respectively)
Answer» A body is projected with initial velocity of $(8^i + 6^j) m/s$ from origin, find angular velocity of body wrt to an axis passing through origin and perpendicular to the x -y plane when it lands. (Here $^i,^j$ are unit vectors corresponding to X, Y axis respectively)

Discussion

47.	A large tank of area A contains liquid of density ρ . A cylinder of density ρ4 and length ℓ, and area a (a≪A) is kept in equilibrium by applying an external vertically downward force. The cylinder is just submerged in liquid. At t = 0 the external force disappears instantaneously. Answer the following questions. The maximum height attained by centre of mass of cylinder from the liquid surface.
Answer» A large tank of area A contains liquid of density $ρ$ . A cylinder of density $\frac{ρ}{4}$ and length ℓ, and area a $(a ≪ A)$ is kept in equilibrium by applying an external vertically downward force. The cylinder is just submerged in liquid. At t = 0 the external force disappears instantaneously. Answer the following questions. The maximum height attained by centre of mass of cylinder from the liquid surface.

Discussion

48.	A small block of a mass m = 1 kg is placed over a wedge of mass M = 4 kg as shown in the figure. Mass ‘m’ is released from rest. All surfaces are smooth. Origin ‘O’ is as shown in the figure. The magnitude of velocity of the wedge when ‘m’ leaves the wedge is
Answer» A small block of a mass m = 1 kg is placed over a wedge of mass M = 4 kg as shown in the figure. Mass ‘m’ is released from rest. All surfaces are smooth. Origin ‘O’ is as shown in the figure. The magnitude of velocity of the wedge when ‘m’ leaves the wedge is

Discussion

49.	A circular coil of radius 3R is carrying current. The ratio of magnetic fields at centroid of coil and at a point distance 4R from center of coil (point is on the axis of coil)
Answer» A circular coil of radius 3R is carrying current. The ratio of magnetic fields at centroid of coil and at a point distance 4R from center of coil (point is on the axis of coil)

Discussion

50.	A capillary tube with inner cross-section in the form of a square of side ′a′ is dipped vertically in a liquid of density ρ and surface tension σ which wets the surface of the capillary tube with an angle of contact θ. The approximate height to which the liquid will rise in the tube is: (Neglect the effect of surface tension at the corners of the capillary tube)
Answer» A capillary tube with inner cross-section in the form of a square of side $^{'} a^{'}$ is dipped vertically in a liquid of density $ρ$ and surface tension $σ$ which wets the surface of the capillary tube with an angle of contact $θ$ . The approximate height to which the liquid will rise in the tube is: (Neglect the effect of surface tension at the corners of the capillary tube)

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Two objects A and B are thrown with the same velocity directly upwards. Suppose if mass of A is greater than B. If the air exerts a constant and equal force of resistance on both bodies . Which body will cover more height

how is the focal length of a spherical mirror affected when the wavelength of the light used is increased?

Why doesnt fire or flame cast a shadow

What is stopping potential .pls describe with full details

If a particle is projected from A normal to the plane calculate (i) Time of flight? (ii) AB=?

a man is looking at a small object placed at a near point. Without altering the position of his eye or the object, he puts a simple microscope of magnifying power 5x before his eyes. The angular magnification achieved is a.) 5 b.) 2.5 c.) 1 d.) 0.2

A solenoid has a core of a material with relative permeability of 500. The windings of the solenoid are insulted from the core and carry a current of 2A. If the number of turns is 1000 per meter, then magnetisation is ??

A particle is projected with a velocity u, at an angle α with the horizontal. Time at which its vertical component of velocity becomes half of its net speed at the highest point will be

On a stationary sail-boat, air is blown at the sails from a fan attached to the boat. The boat will

A police car moving at 22 m/s, chases a motorcyclist. The police man sounds his horn at 176 Hz, while both of them move towards a stationary siren of frequency 165 Hz. Calculate the speed of the motorcycle, if it is given that he does not observe any beats.

A cube of ice is floating in water contained in a vessel. When the ice melts, the level of water in the vessel

In variable state, the rate of flow of heat is controlled by

The motion of a particle executing S.H.M. is given by x = 0.01 sin 100 π ( t + 0.05) , where x is in metres and time is in seconds. The time period is

A satellite is launched into a circular orbit of radius ‘R’ around earth while a second satellite is launched intoan orbit of radius 1.02 R. The percentage difference in the time periods of the two satellites is

Calculate the shortest wavelength in the Balmer series of hydrogen atom. In which region (infrared, visible, ultraviolet) of hydrogen spectrum does this wavelength lie?

If the momentum of a body is increased n times, its kinetic energy increases

At what temperature is the root mean square velocity of gaseous hydrogen molecules is equal to that of oxygen molecules at 47∘C

Monochromatic light of wavelength of 600nm is used in a YDSE. One of the slits is covered by a transparent sheet of thickness 1.8×10−5m made of a material of refractive index 1.6. How many fringes will shift due to the introduction of the sheet?

A weight lifter jerks 220 kg vertically through 1.5 m and holds still at that height for two minutes. What is the work done in lifting and in holding it still respectively

In figure m1=5 kg and F = 1N. Find the acceleration of either block. Describe the motion of m1 if the string breaks but F continues to act.

A conducting disc of radius r rotates with a small but constant angular velocity w about its axis. A uniform magnetic field B exists parallel to the axis of rotation. Find the motional emf between the centre and the periphery of the disc.

What were the observations that made us look for the existence of neutrons?

A bird is sitting on horizontal stretched telephone wires. If its weight is W then the additional tension produced by it in the wires for angle less than 300 will be

Any radiation in the ultra violet region of Hydrogen spectrum is able to eject photoelectrons from a metal. Then the threshold frequency of the metal for a threshold λ=1R=911˙A,is nearly

A particle is executing SHM along x axis given by x=Asinwt. The average velocity during the time interval t=0 to t=Tis

Two metal spheres of same material and radius 'r' are in contact with each other. The gravitational force of attraction between two spheres is given by (k is constant) A)F=kr4 B)=F=k/r2 C)F=k/4r2 D)F=kr2

A truck is moving horizontally with velocity V. A ball is thrown vertically upward with velocity U at an angleθ to the horizontal from the truck relative to it. The horizontal range of the shell relative to the ground is

Suppose the bob of the previous problem has a speed of 1.4 m/s when the string makes an angle of 0.20 radian with the vertical. Find the tension at this instant. You can use cosθ≈ 1−θ2/2 and sinθ≈θ for small θ.

A block of mass m is pushed up a fixed inclined plane of angle 30∘ by a Force of 10 N. Find the work done by the Force in pushing the block up the incline by 10M.

92×576÷2√1296+(?)3+√49

The uncertainty in the momentum of an electron is 1.0×10−5 kg ms−. The uncertainty in the position will be

An iceberg is floating in an ocean. What fraction of its volume is above the water? (Given: density of ice=900 kg/m3 and density of ocean water =1030 kg/m3)

Calculate the stress in a tight wire of a material whose young’s modulus is 19.6×1011 dyne/cm2, so that the speed of the longitudinal wave is 20 times the speed of transverse wave.

Sound with intensity larger than 120 dB appears painful to a person. A small speaker delivers 2.0 W of audio output. How close can the person get to the speaker without hurting his ears?

A plane electromagnetic wave Ez=100cos(6×108t+4x)V/m propagates in a medium of refractive index

Choose the Most appropriate answer. In a tube when a sound wave is created, compression and rarefaction pulses are produced. The rarefaction pulse has pressure.

A box, when hung from a spring balance shows a reading of 50 kg. If the same box is hung from the same spring balance inside an evacuated chamber, the reading on the scale will be

A body covers the first 1/3 of the distance with a velocity of 2 m/s, the next 1/3 with 3 m/s and the rest of the distance with 6 m/s. The average velocity in m/s for covering the whole distance is (assume that the body travels with constant velocity in all the parts in a straight line)

A body is projected with initial velocity of (8^i+6^j) m/s from origin, find angular velocity of body wrt to an axis passing through origin and perpendicular to the x -y plane when it lands. (Here ^i,^j are unit vectors corresponding to X, Y axis respectively)

A small block of a mass m = 1 kg is placed over a wedge of mass M = 4 kg as shown in the figure. Mass ‘m’ is released from rest. All surfaces are smooth. Origin ‘O’ is as shown in the figure. The magnitude of velocity of the wedge when ‘m’ leaves the wedge is

A circular coil of radius 3R is carrying current. The ratio of magnetic fields at centroid of coil and at a point distance 4R from center of coil (point is on the axis of coil)