50278 + Interview Questions in Physics

1.	The equation for the vibration of a string, fixed at both ends vibrating in its third harmonic, is given by y=(0.4 cm)sin[(0.314 cm−1)x]cos[(600πs−1)t]. (a) What is the frequency of vibration ? (b) What are the positions of the nodes? (c) What is the length of the string ? (d) What is the waavelength and the speed of two travelling waves that can interfere to give this vibration ?
Answer» The equation for the vibration of a string, fixed at both ends vibrating in its third harmonic, is given by $y = (0.4 c m) s i n [(0.314 c m^{- 1}) x] c o s [(600 π s^{- 1}) t] .$ (a) What is the frequency of vibration ? (b) What are the positions of the nodes? (c) What is the length of the string ? (d) What is the waavelength and the speed of two travelling waves that can interfere to give this vibration ?

1.

The equation for the vibration of a string, fixed at both ends vibrating in its third harmonic, is given by y=(0.4 cm)sin[(0.314 cm−1)x]cos[(600πs−1)t]. (a) What is the frequency of vibration ? (b) What are the positions of the nodes? (c) What is the length of the string ? (d) What is the waavelength and the speed of two travelling waves that can interfere to give this vibration ?

Answer»

The equation for the vibration of a string, fixed at both ends vibrating in its third harmonic, is given by

$y = (0.4 c m) s i n [(0.314 c m^{- 1}) x] c o s [(600 π s^{- 1}) t] .$

(a) What is the frequency of vibration ? (b) What are the positions of the nodes? (c) What is the length of the string ? (d) What is the waavelength and the speed of two travelling waves that can interfere to give this vibration ?

Discussion

2.	In the figure shown the velocity of lift is 2 m/s while string is winding on the motor shaft with velocity 2 m/s and block A is moving downwards with velocity of 2 m/s, the find out the velocity of block B.
Answer» In the figure shown the velocity of lift is 2 m/s while string is winding on the motor shaft with velocity 2 m/s and block A is moving downwards with velocity of 2 m/s, the find out the velocity of block B.

Discussion

3.	Colour of shining bright star is an indication of its
Answer» Colour of shining bright star is an indication of its

Discussion

4.	The number of ways in which n different prizes can be distributed among m (<n) persons.
Answer» The number of ways in which n different prizes can be distributed among m (<n) persons.

Discussion

5.	Differentiation of sin(x2) w.r.t x is
Answer» Differentiation of $sin (x^{2})$ w.r.t $x$ is

Discussion

6.	A motorcycle starts from rest and accelerates along a straight line at 2.2 m/s2. The speed of sound is 330 m/s. A siren at the starting point remains stationary. When the driver hears the frequency of the siren at 90% of when the motorcycle is stationary, the distance travelled by the motorcyclist is
Answer» A motorcycle starts from rest and accelerates along a straight line at $2.2 m / s^{2} .$ The speed of sound is 330 m/s. A siren at the starting point remains stationary. When the driver hears the frequency of the siren at 90% of when the motorcycle is stationary, the distance travelled by the motorcyclist is

Discussion

7.	A body of mass 100 g is sliding from an inclined plane of inclination 30o. What is the frictional force experienced if μ=1.7
Answer» A body of mass 100 g is sliding from an inclined plane of inclination $30^{o}$ . What is the frictional force experienced if $μ$ =1.7

Discussion

8.	A transpoarent paper (refractive index = 1.45) of thickness 0.02 mm is pasted on one of the slits of a young's double slit experiment which uses monochromatic light of wavelength 620 nm. How many friges will cross through the centre if the paper is removed?
Answer» A transpoarent paper (refractive index = 1.45) of thickness 0.02 mm is pasted on one of the slits of a young's double slit experiment which uses monochromatic light of wavelength 620 nm. How many friges will cross through the centre if the paper is removed?

Discussion

9.	Statement 1: Charge density on a solid conductor is always uniform no matter what the shape. Statement 2: Charges are always on the surface of a conductor and they repel each other so they always arrange to give uniform charge density.
Answer» Statement 1: Charge density on a solid conductor is always uniform no matter what the shape. Statement 2: Charges are always on the surface of a conductor and they repel each other so they always arrange to give uniform charge density.

Discussion

10.	A closed circuit is shown in the figure. Voltage across 6 Ω is measured by voltmeter with resistance of 3 Ω. Find the error in the reading.
Answer» A closed circuit is shown in the figure. Voltage across $6 Ω$ is measured by voltmeter with resistance of $3 Ω$ . Find the error in the reading.

Discussion

11.	A projectile is projected from the level ground in vertical x-y plane (vertical is y axis). The point of projection is considered as the origin. For which of the following initial velocities of projection u and angle of projection θ with the horizontal will the projectile pass through the point (4, 2) (all in m) (Neglect air friction)
Answer» A projectile is projected from the level ground in vertical x-y plane (vertical is y axis). The point of projection is considered as the origin. For which of the following initial velocities of projection u and angle of projection $θ$ with the horizontal will the projectile pass through the point (4, 2) (all in m) (Neglect air friction)

Discussion

12.	Two identical charged spheres are suspended by strings of equal lengths. The strings make an angle of 30∘ with each other. When suspended in a liquid of density 0.8 g /cm3, the angle remains the same. If density of the marterial of the sphere is 1.6 g /cm3, then dielectric constant of the liquid is
Answer» Two identical charged spheres are suspended by strings of equal lengths. The strings make an angle of $30^{\circ}$ with each other. When suspended in a liquid of density $0.8 {g /cm}^{3}$ , the angle remains the same. If density of the marterial of the sphere is $1.6 {g /cm}^{3}$ , then dielectric constant of the liquid is

12.

Two identical charged spheres are suspended by strings of equal lengths. The strings make an angle of 30∘ with each other. When suspended in a liquid of density 0.8 g /cm3, the angle remains the same. If density of the marterial of the sphere is 1.6 g /cm3, then dielectric constant of the liquid is

Answer»

Two identical charged spheres are suspended by strings of equal lengths. The strings make an angle of $30^{\circ}$ with each other. When suspended in a liquid of density $0.8 {g /cm}^{3}$ , the angle remains the same. If density of the marterial of the sphere is $1.6 {g /cm}^{3}$ , then dielectric constant of the liquid is

Discussion

13.	A two-fold increase in intensity of a wave implies an increase of (Given: log102=0.3010)
Answer» A two-fold increase in intensity of a wave implies an increase of (Given: ${log}_{10} 2 = 0.3010$ )

Discussion

14.	Show that the height of the cylinder of maximum volume that can be inscribed in a sphere of radius R is 2R√3. Also, find the maximum volume.
Answer» Show that the height of the cylinder of maximum volume that can be inscribed in a sphere of radius R is $\frac{2 R}{\sqrt{3}}$ . Also, find the maximum volume.

Discussion

15.	Given curve is 1v versus x for a particle under motion is, where v is velocity and x is position. The time taken in seconds by particle to move from x = 4 to x = 12 m is (Given - particle is at origin at t = 0)
Answer» Given curve is $\frac{1}{v}$ versus x for a particle under motion is, where v is velocity and x is position. The time taken in seconds by particle to move from x = 4 to x = 12 m is (Given - particle is at origin at t = 0)

Discussion

16.	Water is filled in a tank upto 4 m height. The base of the tank is at height 1 m above the ground. At what height should the hole be made from the ground, so that the water can be sprayed upto maximum horizontal distance on ground?
Answer» Water is filled in a tank upto $4 m$ height. The base of the tank is at height $1 m$ above the ground. At what height should the hole be made from the ground, so that the water can be sprayed upto maximum horizontal distance on ground?

Discussion

17.	The first allowed excited state of a hydrogen atom is 10.2 eV above its lowest energy (ground) state. To what temperature should hydrogen gas be raised so that inelastic collisions may excite an appreciable number of atoms to their first excited state.
Answer» The first allowed excited state of a hydrogen atom is 10.2 eV above its lowest energy (ground) state. To what temperature should hydrogen gas be raised so that inelastic collisions may excite an appreciable number of atoms to their first excited state.

Discussion

18.	In the above figure D and E respectively represent
Answer» In the above figure D and E respectively represent

Discussion

19.	The work function for tungsten and sodium are 4.5 eV and 2.3 eV respectively. If the threshold wavelength λ for sodium is 5460∘A the value of λ for tungsten is
Answer» The work function for tungsten and sodium are 4.5 eV and 2.3 eV respectively. If the threshold wavelength $λ$ for sodium is $5460 \circ A$ the value of $λ$ for tungsten is

Discussion

20.	A sample of an ideal gas has volume V, pressure P and temperature T. The mass of each molecule of the gas is m. The density of the gas is (k is the Boltzmann's constant )
Answer» A sample of an ideal gas has volume V, pressure P and temperature T. The mass of each molecule of the gas is m. The density of the gas is (k is the Boltzmann's constant )

Discussion

21.	Two discs have same mass and thickness. Their materials are of densities d1 and d2. The ratio of their moments of inertia about an axis passing through the centre and perpnedicular to the plane is
Answer» Two discs have same mass and thickness. Their materials are of densities $d_{1}$ and $d_{2}$ . The ratio of their moments of inertia about an axis passing through the centre and perpnedicular to the plane is

Discussion

22.	If a piece of metal was thought to be magnet, which one of the following observations would offer conclusive evidence
Answer» If a piece of metal was thought to be magnet, which one of the following observations would offer conclusive evidence

Discussion

23.	Electrons in hydrogen-like atoms (Z=3) make transitions from the fifth to the fourth orbit and from the fourth to the third orbit. The resulting radiations are incident normally on a metal plate and eject photoelectrons. The stopping potential for the photoelectrons ejected by the shorter wavelength is 3.95 volts. Calculate the work function of the metal, and the stopping potential(in V) for the photoelectrons ejected by the longer wavelength. (Rydberg constant=1.094×107m−1)
Answer» Electrons in hydrogen-like atoms $(Z = 3)$ make transitions from the fifth to the fourth orbit and from the fourth to the third orbit. The resulting radiations are incident normally on a metal plate and eject photoelectrons. The stopping potential for the photoelectrons ejected by the shorter wavelength is 3.95 volts. Calculate the work function of the metal, and the stopping potential(in V) for the photoelectrons ejected by the longer wavelength. $(Rydberg constant = 1.094 \times 10^{7} m^{- 1})$

Discussion

24.	Suppose the block of the previous problem is pusshed down the incline with a force of 4 N. How far will the block move in the first two seconds after starting from rest ? The mass of the block is 4 kg.
Answer» Suppose the block of the previous problem is pusshed down the incline with a force of 4 N. How far will the block move in the first two seconds after starting from rest ? The mass of the block is 4 kg.

24.

Suppose the block of the previous problem is pusshed down the incline with a force of 4 N. How far will the block move in the first two seconds after starting from rest ? The mass of the block is 4 kg.

Answer»

Suppose the block of the previous problem is pusshed down the incline with a force of 4 N. How far will the block move in the first two seconds after starting from rest ? The mass of the block is 4 kg.

Discussion

25.	A hollow rod of mass, M is kept on a table. The rod is rotating with angular velocity ω when both rings of mass 'm' are situated on axis. Find angular Velocity of rings when they leave the rod.
Answer» A hollow rod of mass, M is kept on a table. The rod is rotating with angular velocity ω when both rings of mass 'm' are situated on axis. Find angular Velocity of rings when they leave the rod.

25.

A hollow rod of mass, M is kept on a table. The rod is rotating with angular velocity ω when both rings of mass 'm' are situated on axis. Find angular Velocity of rings when they leave the rod.

Answer»

A hollow rod of mass, M is kept on a table. The rod is rotating with angular velocity ω when both rings of mass 'm' are situated on axis. Find angular Velocity of rings when they leave the rod.

Discussion

26.	A body of mass is 2 kg is projected at an angle of 30 with horizontal and speed 20 m/s from ground the magnitude of change in velocity is the time of flight is
Answer» A body of mass is 2 kg is projected at an angle of 30 with horizontal and speed 20 m/s from ground the magnitude of change in velocity is the time of flight is

Discussion

27.	A canon can fire shells at speed u. Inclination of its barrel to the horizontal can be changed in steps of Δθ=1∘ ranging from θ1=15∘ to θ2=85∘. Let Rn be the horizontal range for projection angle θ=n∘. If ΔRn=\|Rn−Rn+1\|, the value of n such that ΔRn is maximum is Neglect air resistance.
Answer» A canon can fire shells at speed $u$ . Inclination of its barrel to the horizontal can be changed in steps of $Δ θ = 1^{\circ}$ ranging from $θ_{1} = 15^{\circ} t o θ_{2} = 85^{\circ}$ . Let $R_{n}$ be the horizontal range for projection angle $θ = n^{\circ}$ . If $Δ R_{n} = \| R_{n} - R_{n + 1} \|$ , the value of $n$ such that $Δ R_{n}$ is maximum is Neglect air resistance.

Discussion

28.	A moving coil galvanometer has 50 turns and each turn has an area 2×10−4 m2. The magnetic field produced by the magnet inside the galvanometer is 0.02 T. The torsional constant of the suspension wire is 10−4 Nm−rad−1. When a current flows through the galvanometer, a full-scale deflection occurs if the coil rotates by 0.2 rad. The resistance of the coil of the galvanometer is 50 Ω. This galvanometer is to be converted into an ammeter capable of measuring current in the range 0−1.0 A. For this purpose, a shunt resistance is to be added in parallel to the galvanometer. The value of this shunt resistance, in ohms, is
Answer» A moving coil galvanometer has $50$ turns and each turn has an area $2 \times 10^{- 4} m^{2}$ . The magnetic field produced by the magnet inside the galvanometer is $0.02 T$ . The torsional constant of the suspension wire is $10^{- 4} N m - r a d^{- 1}$ . When a current flows through the galvanometer, a full-scale deflection occurs if the coil rotates by $0.2 r a d$ . The resistance of the coil of the galvanometer is $50 Ω$ . This galvanometer is to be converted into an ammeter capable of measuring current in the range $0 - 1.0 A$ . For this purpose, a shunt resistance is to be added in parallel to the galvanometer. The value of this shunt resistance, in ohms, is

Discussion

29.	There are two isosceles prisms of prism angle =(1.8π)∘ and refractive index 1.5 which are placed with their bases touching each other. This system can act as a converging lens on which parallel rays are incident having distance 1 cm from the line shown in figure. What will be distance of F from base focal length (in meter) on the system ?
Answer» There are two isosceles prisms of prism angle $= {(\frac{1.8}{π})}^{\circ}$ and refractive index $1.5$ which are placed with their bases touching each other. This system can act as a converging lens on which parallel rays are incident having distance $1 cm$ from the line shown in figure. What will be distance of $F$ from base focal length (in meter) on the system ?

Discussion

30.	A receiver and a source of sonic oscillations of frequency 2000 Hz are located on the x-axis. The source swings harmonically along x-axis with circular frequency ω and amplitude 50 cm. At what approximate value of ω will the frequency bandwidth (difference of maximum and minimum frequency) registered by stationary receiver be equal to 200 Hz? (The velocity of sound in air is 340 m/s and assume that the velocity of source is small compared to the velocity of sound)
Answer» A receiver and a source of sonic oscillations of frequency $2000 Hz$ are located on the x-axis. The source swings harmonically along x-axis with circular frequency $ω$ and amplitude $50 cm$ . At what approximate value of $ω$ will the frequency bandwidth (difference of maximum and minimum frequency) registered by stationary receiver be equal to $200 Hz$ ? (The velocity of sound in air is $340 m/s$ and assume that the velocity of source is small compared to the velocity of sound)

Discussion

31.	A particle performs uniform circular motion with an angular momentum L. If the frequency of the particle motion is doubled and its kinetic energy is halved, the angular momentum becomes
Answer» A particle performs uniform circular motion with an angular momentum $L$ . If the frequency of the particle motion is doubled and its kinetic energy is halved, the angular momentum becomes

Discussion

32.	Charges –q, Q and –q are placed at an equal distance on a straight line. If the total potential energy of the system of three charges is zero, then find the ratio Qq.
Answer» Charges –q, Q and –q are placed at an equal distance on a straight line. If the total potential energy of the system of three charges is zero, then find the ratio $\frac{Q}{q}$ .

Discussion

33.	If I0 is the intensity of principal maximum in the single slit diffraction experiment, the intensity of the principal maximum when the slit width is doubled is
Answer» If $I_{0}$ is the intensity of principal maximum in the single slit diffraction experiment, the intensity of the principal maximum when the slit width is doubled is

Discussion

34.	Diameter of telescope required to resolve two objects 20 cm apart from each other and at seperation of 8 km from telescope on cm is (Take λ=400 nm) (Answer upto two decimal places )
Answer» Diameter of telescope required to resolve two objects $20 c m$ apart from each other and at seperation of $8 k m$ from telescope on $c m$ is (Take $λ = 400 n m$ ) (Answer upto two decimal places )

Discussion

35.	A ray of light travelling in the direction 12(^i+√3^j) is incident on a plane mirror. After reflection, it travels along the direction 12(^i−√3^j). The angle of incidence is
Answer» A ray of light travelling in the direction $\frac{1}{2} (^i + \sqrt{3}^j)$ is incident on a plane mirror. After reflection, it travels along the direction $\frac{1}{2} (^i - \sqrt{3}^j)$ . The angle of incidence is

Discussion

36.	The temperature of a liquid drops from 365 K to 361 K in 2 min. Find the time during which temperature of the liquid drops from 344 K to 342 K. [Take the room temperature as 293 K]
Answer» The temperature of a liquid drops from $365 K$ to $361 K$ in $2 min$ . Find the time during which temperature of the liquid drops from $344 K$ to $342 K$ . [Take the room temperature as $293 K$ ]

Discussion

37.	Two particles undergo SHM along parallel lines with the same time period (T) and equal amplitudes. At a particular instant. one particle is at its extreme position while the other is at its mean position. They move the same direction. They will cross each other after a further time of
Answer» Two particles undergo SHM along parallel lines with the same time period $(T)$ and equal amplitudes. At a particular instant. one particle is at its extreme position while the other is at its mean position. They move the same direction. They will cross each other after a further time of

Discussion

38.	A stationary man observes that the rain is falling vertically downward. When he starts running with a velocity of 12 km/h, he observes that the rain is falling at an angle 60∘ with the vertical. The actual velocity of rain is
Answer» A stationary man observes that the rain is falling vertically downward. When he starts running with a velocity of $12 km/h$ , he observes that the rain is falling at an angle $60^{\circ}$ with the vertical. The actual velocity of rain is

Discussion

39.	It is given that 5 main scale division of a vernier caliper coincide with 6 vernier scale divisions. When jaws are closed zeros of both scale do not coincide and has a negative zero error. Find magnitude of this zero error in mm. 1 main scale division is equal to 1mm.
Answer» It is given that 5 main scale division of a vernier caliper coincide with 6 vernier scale divisions. When jaws are closed zeros of both scale do not coincide and has a negative zero error. Find magnitude of this zero error in mm. 1 main scale division is equal to 1mm.

Discussion

40.	Find the direction of friction on A and B respectively at the common surface between blocks A and B for the figure shown.
Answer» Find the direction of friction on $A$ and $B$ respectively at the common surface between blocks $A$ and $B$ for the figure shown.

Discussion

41.	A wire of resistor R is bent into a circular ring of radius r. Equivalent resistance between two points X and Y on its circumference, when angle XOY is α, can be given by
Answer» A wire of resistor R is bent into a circular ring of radius r. Equivalent resistance between two points X and Y on its circumference, when angle XOY is $α$ , can be given by

Discussion

42.	A plate of mass M is moved with constant velocity v against dust particles moving with velocity u in opposite direction as shown. The density of the dust is ρ and plate area is A. Find the force F required to keep the plate moving with uniform velocity.
Answer» A plate of mass $M$ is moved with constant velocity $v$ against dust particles moving with velocity $u$ in opposite direction as shown. The density of the dust is $ρ$ and plate area is $A$ . Find the force $F$ required to keep the plate moving with uniform velocity.

Discussion

43.	A force F is applied on a block at an angle θ with the horizontal as shown in figure. Given (μs>μk). Find the correct graph between frictional force and time. (where t= time)
Answer» A force $F$ is applied on a block at an angle $θ$ with the horizontal as shown in figure. Given $(μ_{s} > μ_{k})$ . Find the correct graph between frictional force and time. (where $t =$ time)

Discussion

44.	The value of R in the given figure so that there is no current in the 10Ω resistor is.
Answer» The value of R in the given figure so that there is no current in the $10 Ω$ resistor is.

Discussion

45.	A uniform rod of length l and mass m is hung from two strings of equal length from a ceiling as shown in figure. Determine the tensions in the strings?
Answer» A uniform rod of length $l$ and mass $m$ is hung from two strings of equal length from a ceiling as shown in figure. Determine the tensions in the strings?

Discussion

46.	A particle starts from rest at t=0 and moves in a straight line with acceleration as shown in the following figure. The velocity of the particle at t=3 seconds is
Answer» A particle starts from rest at $t = 0$ and moves in a straight line with acceleration as shown in the following figure. The velocity of the particle at $t = 3$ seconds is

Discussion

47.	The density of a material in CGS system of units is 4 g/cm3. In a system of units in which unit of length is 10 cm and unit of mass is 100 g, the value of density of material will be
Answer» The density of a material in CGS system of units is $4 {g/cm}^{3}$ . In a system of units in which unit of length is $10 cm$ and unit of mass is $100 g$ , the value of density of material will be

Discussion

48.	A vessel contains water up to a height of 20 cm and above it an oil up to another 20 cm. The refractive indices of the water and the oil are 1.33 and 1.30 respectively. Find the apparent depth of the vessel when viewed from above.
Answer» A vessel contains water up to a height of 20 cm and above it an oil up to another 20 cm. The refractive indices of the water and the oil are 1.33 and 1.30 respectively. Find the apparent depth of the vessel when viewed from above.

Discussion

49.	Comment on the correctness of the following two statements based on the given situation. Consider a line of length ‘l’ and uniform charge density λ. Assume a Gaussian surface S, a cylinder of radius R and height h. Statement 1: φ=flux through S=λHϵ0 Statement 2: \|→E\|at all the points on its curved surface=λϵ02πR
Answer» Comment on the correctness of the following two statements based on the given situation. Consider a line of length ‘l’ and uniform charge density $λ$ . Assume a Gaussian surface S, a cylinder of radius R and height h. Statement 1: $φ = f l u x t h r o u g h S = \frac{λ H}{ϵ_{0}}$ Statement 2: $\| \to E \| a t a l l t h e p o i n t s o n i t s c u r v e d s u r f a c e = \frac{λ}{ϵ_{0} 2 π R}$

49.

Comment on the correctness of the following two statements based on the given situation. Consider a line of length ‘l’ and uniform charge density λ. Assume a Gaussian surface S, a cylinder of radius R and height h. Statement 1: φ=flux through S=λHϵ0 Statement 2: |→E|at all the points on its curved surface=λϵ02πR

Answer»

Comment on the correctness of the following two statements based on the given situation.
Consider a line of length ‘l’ and uniform charge density $λ$ . Assume a Gaussian surface S, a cylinder of radius R and height h.

Statement 1: $φ = f l u x t h r o u g h S = \frac{λ H}{ϵ_{0}}$

Statement 2: $| \to E | a t a l l t h e p o i n t s o n i t s c u r v e d s u r f a c e = \frac{λ}{ϵ_{0} 2 π R}$

Discussion

50.	If cells are joined in parallel, they have _______.
Answer» If cells are joined in parallel, they have _______.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

In the figure shown the velocity of lift is 2 m/s while string is winding on the motor shaft with velocity 2 m/s and block A is moving downwards with velocity of 2 m/s, the find out the velocity of block B.

Colour of shining bright star is an indication of its

The number of ways in which n different prizes can be distributed among m (&lt;n) persons.

Differentiation of sin(x2) w.r.t x is

A body of mass 100 g is sliding from an inclined plane of inclination 30o. What is the frictional force experienced if μ=1.7

A transpoarent paper (refractive index = 1.45) of thickness 0.02 mm is pasted on one of the slits of a young's double slit experiment which uses monochromatic light of wavelength 620 nm. How many friges will cross through the centre if the paper is removed?

Statement 1: Charge density on a solid conductor is always uniform no matter what the shape. Statement 2: Charges are always on the surface of a conductor and they repel each other so they always arrange to give uniform charge density.

A closed circuit is shown in the figure. Voltage across 6 Ω is measured by voltmeter with resistance of 3 Ω. Find the error in the reading.

A two-fold increase in intensity of a wave implies an increase of (Given: log102=0.3010)

Show that the height of the cylinder of maximum volume that can be inscribed in a sphere of radius R is 2R√3. Also, find the maximum volume.

Given curve is 1v versus x for a particle under motion is, where v is velocity and x is position. The time taken in seconds by particle to move from x = 4 to x = 12 m is (Given - particle is at origin at t = 0)

Water is filled in a tank upto 4 m height. The base of the tank is at height 1 m above the ground. At what height should the hole be made from the ground, so that the water can be sprayed upto maximum horizontal distance on ground?

The first allowed excited state of a hydrogen atom is 10.2 eV above its lowest energy (ground) state. To what temperature should hydrogen gas be raised so that inelastic collisions may excite an appreciable number of atoms to their first excited state.

In the above figure D and E respectively represent

The work function for tungsten and sodium are 4.5 eV and 2.3 eV respectively. If the threshold wavelength λ for sodium is 5460∘A the value of λ for tungsten is

A sample of an ideal gas has volume V, pressure P and temperature T. The mass of each molecule of the gas is m. The density of the gas is (k is the Boltzmann's constant )

Two discs have same mass and thickness. Their materials are of densities d1 and d2. The ratio of their moments of inertia about an axis passing through the centre and perpnedicular to the plane is

If a piece of metal was thought to be magnet, which one of the following observations would offer conclusive evidence

Suppose the block of the previous problem is pusshed down the incline with a force of 4 N. How far will the block move in the first two seconds after starting from rest ? The mass of the block is 4 kg.

A hollow rod of mass, M is kept on a table. The rod is rotating with angular velocity ω when both rings of mass 'm' are situated on axis. Find angular Velocity of rings when they leave the rod.

A body of mass is 2 kg is projected at an angle of 30 with horizontal and speed 20 m/s from ground the magnitude of change in velocity is the time of flight is

A particle performs uniform circular motion with an angular momentum L. If the frequency of the particle motion is doubled and its kinetic energy is halved, the angular momentum becomes

Charges –q, Q and –q are placed at an equal distance on a straight line. If the total potential energy of the system of three charges is zero, then find the ratio Qq.

If I0 is the intensity of principal maximum in the single slit diffraction experiment, the intensity of the principal maximum when the slit width is doubled is

Diameter of telescope required to resolve two objects 20 cm apart from each other and at seperation of 8 km from telescope on cm is (Take λ=400 nm) (Answer upto two decimal places )

A ray of light travelling in the direction 12(^i+√3^j) is incident on a plane mirror. After reflection, it travels along the direction 12(^i−√3^j). The angle of incidence is

The temperature of a liquid drops from 365 K to 361 K in 2 min. Find the time during which temperature of the liquid drops from 344 K to 342 K. [Take the room temperature as 293 K]

Two particles undergo SHM along parallel lines with the same time period (T) and equal amplitudes. At a particular instant. one particle is at its extreme position while the other is at its mean position. They move the same direction. They will cross each other after a further time of

A stationary man observes that the rain is falling vertically downward. When he starts running with a velocity of 12 km/h, he observes that the rain is falling at an angle 60∘ with the vertical. The actual velocity of rain is

It is given that 5 main scale division of a vernier caliper coincide with 6 vernier scale divisions. When jaws are closed zeros of both scale do not coincide and has a negative zero error. Find magnitude of this zero error in mm. 1 main scale division is equal to 1mm.

Find the direction of friction on A and B respectively at the common surface between blocks A and B for the figure shown.

A wire of resistor R is bent into a circular ring of radius r. Equivalent resistance between two points X and Y on its circumference, when angle XOY is α, can be given by

A plate of mass M is moved with constant velocity v against dust particles moving with velocity u in opposite direction as shown. The density of the dust is ρ and plate area is A. Find the force F required to keep the plate moving with uniform velocity.

A force F is applied on a block at an angle θ with the horizontal as shown in figure. Given (μs&gt;μk). Find the correct graph between frictional force and time. (where t= time)

The value of R in the given figure so that there is no current in the 10Ω resistor is.

A uniform rod of length l and mass m is hung from two strings of equal length from a ceiling as shown in figure. Determine the tensions in the strings?

A particle starts from rest at t=0 and moves in a straight line with acceleration as shown in the following figure. The velocity of the particle at t=3 seconds is

The density of a material in CGS system of units is 4 g/cm3. In a system of units in which unit of length is 10 cm and unit of mass is 100 g, the value of density of material will be

A vessel contains water up to a height of 20 cm and above it an oil up to another 20 cm. The refractive indices of the water and the oil are 1.33 and 1.30 respectively. Find the apparent depth of the vessel when viewed from above.

If cells are joined in parallel, they have _______.

The number of ways in which n different prizes can be distributed among m (<n) persons.

A force F is applied on a block at an angle θ with the horizontal as shown in figure. Given (μs>μk). Find the correct graph between frictional force and time. (where t= time)