50278 + Interview Questions in Physics

1.	Example of inertia of direction.
Answer» Example of inertia of direction.

Discussion

2.	A metal ball of mass 2 kg moving with speed of 36 kmph is having a collision with a stationary ball of mass 2 kg. If after collision, both the balls move together, the loss in kinetic energy due to collision is:
Answer» A metal ball of mass $2 kg$ moving with speed of $36 kmph$ is having a collision with a stationary ball of mass $2 kg$ . If after collision, both the balls move together, the loss in kinetic energy due to collision is:

Discussion

3.	An optical instrument used for angular magnification has a 25 D objective and a 20 D eyepiece. The tube length is 25 cm when the eye is least strained. (a) Whether it is a microscope or a telescope? (b) What is the angular magnification produced?
Answer» An optical instrument used for angular magnification has a 25 D objective and a 20 D eyepiece. The tube length is 25 cm when the eye is least strained. (a) Whether it is a microscope or a telescope? (b) What is the angular magnification produced?

3.

An optical instrument used for angular magnification has a 25 D objective and a 20 D eyepiece. The tube length is 25 cm when the eye is least strained. (a) Whether it is a microscope or a telescope? (b) What is the angular magnification produced?

Answer»

An optical instrument used for angular magnification has a 25 D objective and a 20 D eyepiece. The tube length is 25 cm when the eye is least strained.

(a) Whether it is a microscope or a telescope?

(b) What is the angular magnification produced?

Discussion

4.	A mercury Celsius thermometer is transferred from melting ice to a hot liquid. The mercury rises to 910th of the distance between the two fixed points. Find the temperature of the liquid in Fahrenheit scale.
Answer» A mercury Celsius thermometer is transferred from melting ice to a hot liquid. The mercury rises to $\frac{9}{10}$ th of the distance between the two fixed points. Find the temperature of the liquid in Fahrenheit scale.

Discussion

5.	Two thermometers X and Y have ice points marked at 15∘ and 25∘ and steam points marked as 75∘ and 125∘ respectively. When thermometer X measures the temperature of a bath as 60∘ on it, what would thermometer Y read when it is used to measure the temperature of the same bath?
Answer» Two thermometers X and Y have ice points marked at $15^{\circ}$ and $25^{\circ}$ and steam points marked as $75^{\circ}$ and $125^{\circ}$ respectively. When thermometer X measures the temperature of a bath as $60^{\circ}$ on it, what would thermometer Y read when it is used to measure the temperature of the same bath?

Discussion

6.	A stone tied to the end of a string 100 cm long is whirled in a horizontal circle with a constant speed. If the stone makes 14 revolutions in 22 s, then the acceleration of the stone is:
Answer» A stone tied to the end of a string 100 cm long is whirled in a horizontal circle with a constant speed. If the stone makes 14 revolutions in 22 s, then the acceleration of the stone is:

Discussion

7.	The image for the converging beam after refraction through the curved surface is formed at
Answer» The image for the converging beam after refraction through the curved surface is formed at

Discussion

8.	(p) A small solid cylinder of radius r and mass M slides down a smooth hill of height h from rest and gets onto the plank of mass M lying on the smooth horizontal plane at the base of the hill as shown in the figure. Due to friction between the cylinder and plank, the cylinder slows down and starts rolling without friction over the plank. While the cylinder is rolling (without sliding) over the plank, the velocity of the plank is vp, the velocity of centre of mass of the cylinder is vc and angular velocity of the cylinder is “ω”. The coefficient of friction between the cylinder and plank is , while gravity (g) is uniform in the space. [Assume that height of the plank is negligible.] The velocity of centre of mass of the cylinder after it starts pure rolling is
Answer» (p) A small solid cylinder of radius r and mass M slides down a smooth hill of height h from rest and gets onto the plank of mass M lying on the smooth horizontal plane at the base of the hill as shown in the figure. Due to friction between the cylinder and plank, the cylinder slows down and starts rolling without friction over the plank. While the cylinder is rolling (without sliding) over the plank, the velocity of the plank is $v_{p}$ , the velocity of centre of mass of the cylinder is $v_{c}$ and angular velocity of the cylinder is “ $ω$ ”. The coefficient of friction between the cylinder and plank is, while gravity (g) is uniform in the space. [Assume that height of the plank is negligible.] The velocity of centre of mass of the cylinder after it starts pure rolling is

Discussion

9.	A uniform disc of radius a and mass m, is rotating freely with angular speed ω in a horizontal plane about a smooth ﬁxed vertical axis through its centre. A particle, also of mass m, is suddenly attached to the rim of the disc and rotates with it. The new angular speed is
Answer» A uniform disc of radius a and mass m, is rotating freely with angular speed $ω$ in a horizontal plane about a smooth ﬁxed vertical axis through its centre. A particle, also of mass m, is suddenly attached to the rim of the disc and rotates with it. The new angular speed is

Discussion

10.	A non conducting disc of radius a and uniform positive surface charge density σ is placed on the ground with its axis vertical. A particle of mass m and charge q is dropped, along the axis of the disc from a height H with zero initial velocity. It was observed that its velocity becomes zero just when it reaches the disc. The value of 3Ha is (Given qm=4ϵogσ)
Answer» A non conducting disc of radius $a$ and uniform positive surface charge density $σ$ is placed on the ground with its axis vertical. A particle of mass $m$ and charge $q$ is dropped, along the axis of the disc from a height $H$ with zero initial velocity. It was observed that its velocity becomes zero just when it reaches the disc. The value of $\frac{3 H}{a}$ is (Given $\frac{q}{m} = \frac{4 ϵ_{o} g}{σ}$ )

Discussion

11.	A horizontal solid cylinder (of mass m) is pivoted about its longitudinal axis. To the end of a thread wrapped on the cylinder a block (of mass 2m) is attached, as shown. If the system is left free, acceleration of the block (in ms−2) is (string is massless and there is no slipping anywhere)
Answer» A horizontal solid cylinder (of mass $m$ ) is pivoted about its longitudinal axis. To the end of a thread wrapped on the cylinder a block (of mass $2 m$ ) is attached, as shown. If the system is left free, acceleration of the block (in ${ms}^{- 2}$ ) is (string is massless and there is no slipping anywhere)

Discussion

12.	Which of the following graph shows the relation between shear stress and velocity gradient for a non-Newtonian fluid?
Answer» Which of the following graph shows the relation between shear stress and velocity gradient for a non-Newtonian fluid?

Discussion

13.	A square is made by joining four rods each of mass m and length L each. Its moment of inertia about an axis PQ, on its plane and passing through one of its corners (as shown in the figure) will be:
Answer» A square is made by joining four rods each of mass $m$ and length $L$ each. Its moment of inertia about an axis $P Q,$ on its plane and passing through one of its corners (as shown in the figure) will be:

Discussion

14.	Match the corresponding entities COLUMN 1. COLUMN 2 (A)m=-2. (a) convex mirror (B)m=-1/2. (b)concave mirror (C)m=2. (c)real image (D)m=+1/2. (d) virtual image Can you pease provide the explanation too.
Answer» Match the corresponding entities COLUMN 1. COLUMN 2 (A)m=-2. (a) convex mirror (B)m=-1/2. (b)concave mirror (C)m=2. (c)real image (D)m=+1/2. (d) virtual image Can you pease provide the explanation too.

14.

Match the corresponding entities COLUMN 1. COLUMN 2 (A)m=-2. (a) convex mirror (B)m=-1/2. (b)concave mirror (C)m=2. (c)real image (D)m=+1/2. (d) virtual image Can you pease provide the explanation too.

Answer»

Match the corresponding entities

COLUMN 1. COLUMN 2

(A)m=-2. (a) convex mirror

(B)m=-1/2. (b)concave mirror

(C)m=2. (c)real image

(D)m=+1/2. (d) virtual image

Can you pease provide the explanation too.

Discussion

15.	The kα x-ray emission line of tungsten occurs at λ=0.2 ∘A. If energy difference between K and L level in this atom is approximately (10n) keV, then n is [Take hc = 1200 eV-nm]
Answer» The $k_{α}$ x-ray emission line of tungsten occurs at $λ = 0.2 \circ A$ . If energy difference between K and L level in this atom is approximately (10n) keV, then n is [Take hc = 1200 eV-nm]

Discussion

16.	Consider the refraction of light ray as shown in the figure below. Incident ray is rotating with constant angular velocity 2 rad/s. What is the angular velocity of refracted ray, when the angle of incidence becomes 30∘? (Given ratio of refractive indices n1n2=√3)
Answer» Consider the refraction of light ray as shown in the figure below. Incident ray is rotating with constant angular velocity $2 r a d / s$ . What is the angular velocity of refracted ray, when the angle of incidence becomes $30^{\circ}$ ? (Given ratio of refractive indices $\frac{n_{1}}{n_{2}} = \sqrt{3}$ )

16.

Consider the refraction of light ray as shown in the figure below. Incident ray is rotating with constant angular velocity 2 rad/s. What is the angular velocity of refracted ray, when the angle of incidence becomes 30∘? (Given ratio of refractive indices n1n2=√3)

Answer»

Consider the refraction of light ray as shown in the figure below. Incident ray is rotating with constant angular velocity $2 r a d / s$ . What is the angular velocity of refracted ray, when the angle of incidence becomes $30^{\circ}$ ? (Given ratio of refractive indices $\frac{n_{1}}{n_{2}} = \sqrt{3}$ )

Discussion

17.	All the curves in Column 1 are parabolic and those in Column 2 and Column 3 are straight lines. ‘x’, ‘v’ and ‘a’ denote position, velocity and acceleration of a particle and consider positive in the direction of increasing ‘x’. Which of the following options is the only INCORRECT combination?
Answer» All the curves in Column 1 are parabolic and those in Column 2 and Column 3 are straight lines. ‘x’, ‘v’ and ‘a’ denote position, velocity and acceleration of a particle and consider positive in the direction of increasing ‘x’. Which of the following options is the only INCORRECT combination?

17.

All the curves in Column 1 are parabolic and those in Column 2 and Column 3 are straight lines. ‘x’, ‘v’ and ‘a’ denote position, velocity and acceleration of a particle and consider positive in the direction of increasing ‘x’. Which of the following options is the only INCORRECT combination?

Answer»

All the curves in Column 1 are parabolic and those in Column 2 and Column 3 are straight lines.

‘x’, ‘v’ and ‘a’ denote position, velocity and acceleration of a particle and consider positive in the direction of increasing ‘x’.

Which of the following options is the only INCORRECT combination?

Discussion

18.	A body is projected vertically upward with speed 40 m/s. The distance travelled by the body in last 2 second of the journey is [g=10 m/s2]
Answer» A body is projected vertically upward with speed $40 m / s$ . The distance travelled by the body in last 2 second of the journey is $[g = 10 m / s^{2}]$

Discussion

19.	Find the frictional force between the two blocks. Take g=10 m/s2.
Answer» Find the frictional force between the two blocks. Take $g = 10 {m/s}^{2}$ .

Discussion

20.	The volume of a cube is increasing at the rate of 8cm3/s. How fast is the surface area increasing when the length of an edge is 12 cm?
Answer» The volume of a cube is increasing at the rate of $8 c m^{3} / s$ . How fast is the surface area increasing when the length of an edge is 12 cm?

Discussion

21.	Two unknown resistances X and Y are connected in left and right gaps of a metre bridge and the balancing point is obtained at 50 cm from left. When a 20 Ω resistance is connected in series with X, the balancing point is at 60 cm from left. The values of X and Y respectively (in ohms) are
Answer» Two unknown resistances X and Y are connected in left and right gaps of a metre bridge and the balancing point is obtained at 50 cm from left. When a $20 Ω$ resistance is connected in series with X, the balancing point is at 60 cm from left. The values of X and Y respectively (in ohms) are

Discussion

22.	In a region, the potential is represented by V(x,y,z)=6x−8xy+6yz, where V is in volts and x, y and z are in metres. The electric force experienced by a charge of 2 Coulomb situated at point (1,1,1) is
Answer» In a region, the potential is represented by $V (x, y, z) = 6 x - 8 x y + 6 y z$ , where $V$ is in volts and $x$ , $y$ and $z$ are in metres. The electric force experienced by a charge of $2$ Coulomb situated at point $(1, 1, 1)$ is

Discussion

23.	Two tuning forks when sounded together produce 6 beats/s. The first fork has the frequency 3% higher than a standard one and the second has the frequency 2% less than the standard fork. The frequencies for the forks are
Answer» Two tuning forks when sounded together produce 6 beats/s. The first fork has the frequency 3% higher than a standard one and the second has the frequency 2% less than the standard fork. The frequencies for the forks are

Discussion

24.	A particle moves along the path ABCA with a constant speed starting from A. Part BC is circular with centre at A. The magnitude of displacement (from A) versus time graph will be
Answer» A particle moves along the path $A B C A$ with a constant speed starting from $A$ . Part $B C$ is circular with centre at $A$ . The magnitude of displacement (from $A$ ) versus time graph will be

Discussion

25.	Do Broglie equation describes the relationship of wavelength associated with the motion of an electron and its
Answer» Do Broglie equation describes the relationship of wavelength associated with the motion of an electron and its

Discussion

26.	What is ionisation energy?
Answer» What is ionisation energy?

Discussion

27.	If we assume that there exists heaven such that 1 year on earth is equal to 1 day on heaven then what could be the possible reason for this phenomenon?
Answer» If we assume that there exists heaven such that 1 year on earth is equal to 1 day on heaven then what could be the possible reason for this phenomenon?

Discussion

28.	Explain briefly about phasor in angular simple harmonic motion
Answer» Explain briefly about phasor in angular simple harmonic motion

Discussion

29.	if a train is moving on the circular path of 1500m radius at the rate of 66km per hour,find the angle in radian,if it has in 10sec
Answer» if a train is moving on the circular path of 1500m radius at the rate of 66km per hour,find the angle in radian,if it has in 10sec

Discussion

30.	Each division on the main scale of a Vernier callipers is 1mm. Which of the following Vernier scales give the least count equal to 0.01mm ? (A)9 mm divided into 100 divisions (B)99 mm divided into 100 divisions
Answer» Each division on the main scale of a Vernier callipers is 1mm. Which of the following Vernier scales give the least count equal to 0.01mm ? (A)9 mm divided into 100 divisions (B)99 mm divided into 100 divisions

30.

Each division on the main scale of a Vernier callipers is 1mm. Which of the following Vernier scales give the least count equal to 0.01mm ? (A)9 mm divided into 100 divisions (B)99 mm divided into 100 divisions

Answer»

Each division on the main scale of a Vernier callipers is 1mm. Which of the following Vernier scales give the least count equal to 0.01mm ?

(A)9 mm divided into 100 divisions

(B)99 mm divided into 100 divisions

Discussion

31.	Three forces are acting on a body in which option can be body in equilibrium A. 2 , 4 , 5 B 1, 2, 3 C 3, 3, 7 D 5, 2, 1
Answer» Three forces are acting on a body in which option can be body in equilibrium A. 2 , 4 , 5 B 1, 2, 3 C 3, 3, 7 D 5, 2, 1

31.

Three forces are acting on a body in which option can be body in equilibrium A. 2 , 4 , 5 B 1, 2, 3 C 3, 3, 7 D 5, 2, 1

Answer»

Three forces are acting on a body in which option can be body in equilibrium

A. 2 , 4 , 5

B 1, 2, 3

C 3, 3, 7

D 5, 2, 1

Discussion

32.	According to Bernoulli's principle ------ as the velocity of an incompressible fluid increases , the pressure reduces . Please explain why this happens
Answer» According to Bernoulli's principle ------ as the velocity of an incompressible fluid increases , the pressure reduces . Please explain why this happens

Discussion

33.	The meter is defined as the distance traveled by light in vacuum in 1/299792458 sec. Why it has been chosen not anything else?
Answer» The meter is defined as the distance traveled by light in vacuum in 1/299792458 sec. Why it has been chosen not anything else?

Discussion

34.	The NOR gate is OR gate followed by
Answer» The NOR gate is OR gate followed by

Discussion

35.	A particle is falling freely under the action of gravity. It covers a distance x1 in the first ′t′ seconds and distance x2 in the next ′t′ seconds, then ′t′ is given by
Answer» A particle is falling freely under the action of gravity. It covers a distance $x_{1}$ in the first $^{'} t^{'}$ seconds and distance $x_{2}$ in the next $^{'} t^{'}$ seconds, then $^{'} t^{'}$ is given by

Discussion

36.	The velocity and acceleration amplitudes of body executing simple harmonic motion is
Answer» The velocity and acceleration amplitudes of body executing simple harmonic motion is

Discussion

37.	Inside the toroid, in which direction does the magnetic field point?
Answer» Inside the toroid, in which direction does the magnetic field point?

Discussion

38.	ΔABC is a right angled triangle right angled at B and BD is the altitude from B on side AC. If BD=9 cm and inradii of ΔABC,ΔABD and ΔBCD are r1,r2 and r3 respectively, then r1+r2+r3 is
Answer» $Δ A B C$ is a right angled triangle right angled at $B$ and $B D$ is the altitude from $B$ on side $A C$ . If $B D = 9$ cm and inradii of $Δ A B C, Δ A B D$ and $Δ B C D$ are $r_{1}, r_{2}$ and $r_{3}$ respectively, then $r_{1} + r_{2} + r_{3}$ is

Discussion

39.	A simple harmonic oscillator has an amplitude a and time period T. The time required by it to travel from x = a to x = a2 is [CBSE PMT 1992; SCRA 1996; BHU 1997]
Answer» A simple harmonic oscillator has an amplitude a and time period T. The time required by it to travel from x = a to x = $\frac{a}{2}$ is [CBSE PMT 1992; SCRA 1996; BHU 1997]

39.

A simple harmonic oscillator has an amplitude a and time period T. The time required by it to travel from x = a to x = a2 is [CBSE PMT 1992; SCRA 1996; BHU 1997]

Answer»

A simple harmonic oscillator has an amplitude a and time period T. The time required by it to travel from x = a to x = $\frac{a}{2}$ is

[CBSE PMT 1992; SCRA 1996; BHU 1997]

Discussion

40.	Let →a, →b and →c be 3 mutually perpendicular unit vectors. If →d is a unit vector which is equally inclined to →a, →b and →c, then the value of \|→a+→b+→c+→d\|2 is p+√q then p+q is
Answer» Let $\to a$ , $\to b$ and $\to c$ be 3 mutually perpendicular unit vectors. If $\to d$ is a unit vector which is equally inclined to $\to a$ , $\to b$ and $\to c$ , then the value of $\| \to a + \to b + \to c + \to d \|^{2}$ is $p + \sqrt{q}$ then $p + q$ is

Discussion

41.	If →A.→B=\|→A×→B\|, find angle between →A and →B.
Answer» If $\to A . \to B = \| \to A \times \to B \|,$ find angle between $\to A$ and $\to B .$

Discussion

42.	A 0.10 kg block oscillates back and forth along a horizontal surface. Its displacement from the origin is given by: x=(10cm)cos[(10rads)t+π2rad] . What is the maximum acceleration experienced by the block [AMU (Engg.) 2000]
Answer» A 0.10 kg block oscillates back and forth along a horizontal surface. Its displacement from the origin is given by: $x = (10 c m) c o s [(10 r a d s) t + \frac{π}{2} r a d]$ . What is the maximum acceleration experienced by the block [AMU (Engg.) 2000]

42.

A 0.10 kg block oscillates back and forth along a horizontal surface. Its displacement from the origin is given by: x=(10cm)cos[(10rads)t+π2rad] . What is the maximum acceleration experienced by the block [AMU (Engg.) 2000]

Answer»

A 0.10 kg block oscillates back and forth along a horizontal surface. Its displacement from the origin is given by: $x = (10 c m) c o s [(10 r a d s) t + \frac{π}{2} r a d]$ . What is the maximum acceleration experienced by the block

[AMU (Engg.) 2000]

Discussion

43.	A caesium photocell, with a steady potential difference of 60V across, is illuminated by a bright point source of light 50 cm away. When the same light is placed 1m away the photoelectrons emitted from the cell
Answer» A caesium photocell, with a steady potential difference of 60V across, is illuminated by a bright point source of light 50 cm away. When the same light is placed 1m away the photoelectrons emitted from the cell

Discussion

44.	A circular plate of uniform thickness has a diameter of 28 cm. A circular portion of diameter 21 cm is removed from the plate as shown. O is the centre of mass of the complete plate. The position of centre of mass of the remaining portion will shift towards left from O by
Answer» A circular plate of uniform thickness has a diameter of $28 cm$ . A circular portion of diameter $21 cm$ is removed from the plate as shown. $O$ is the centre of mass of the complete plate. The position of centre of mass of the remaining portion will shift towards left from $O$ by

Discussion

45.	A particle of mass 200 gm executes S.H.M. The restoring force is provided by a spring of force constant 80 N / m. The time period of oscillations is.
Answer» A particle of mass 200 gm executes S.H.M. The restoring force is provided by a spring of force constant 80 N / m. The time period of oscillations is.

45.

A particle of mass 200 gm executes S.H.M. The restoring force is provided by a spring of force constant 80 N / m. The time period of oscillations is.

Answer»

A particle of mass 200 gm executes S.H.M. The restoring force is provided by a spring of force constant 80 N / m. The time period of oscillations is.

Discussion

46.	A ball is thrown vertically upward from the ground. It reaches a maximum height of 20 m in 5 sec. After what time, it will reach the ground from its maximum height position?
Answer» A ball is thrown vertically upward from the ground. It reaches a maximum height of 20 m in 5 sec. After what time, it will reach the ground from its maximum height position?

46.

A ball is thrown vertically upward from the ground. It reaches a maximum height of 20 m in 5 sec. After what time, it will reach the ground from its maximum height position?

Answer»

A ball is thrown vertically upward from the ground. It reaches a maximum height of 20 m in 5 sec. After what time, it will reach the ground from its maximum height position?

Discussion

47.	Neglecting the air resistance, the time of flight of a projectile is determined by
Answer» Neglecting the air resistance, the time of flight of a projectile is determined by

Discussion

48.	What is electrostatic potential map and explain it's use
Answer» What is electrostatic potential map and explain it's use

Discussion

49.	A particle is moving on a circular path with constant speed, then its acceleration will be
Answer» A particle is moving on a circular path with constant speed, then its acceleration will be

Discussion

50.	Two liquids of the same mass which are at temperatures 20∘C and 40∘C are mixed to form a composite liquid. If the temperature of the mixture is 32∘C, then the ratio of their heat capacities is
Answer» Two liquids of the same mass which are at temperatures $20^{\circ} C$ and $40^{\circ} C$ are mixed to form a composite liquid. If the temperature of the mixture is $32^{\circ} C$ , then the ratio of their heat capacities is

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Example of inertia of direction.

A metal ball of mass 2 kg moving with speed of 36 kmph is having a collision with a stationary ball of mass 2 kg. If after collision, both the balls move together, the loss in kinetic energy due to collision is:

An optical instrument used for angular magnification has a 25 D objective and a 20 D eyepiece. The tube length is 25 cm when the eye is least strained. (a) Whether it is a microscope or a telescope? (b) What is the angular magnification produced?

A mercury Celsius thermometer is transferred from melting ice to a hot liquid. The mercury rises to 910th of the distance between the two fixed points. Find the temperature of the liquid in Fahrenheit scale.

Two thermometers X and Y have ice points marked at 15∘ and 25∘ and steam points marked as 75∘ and 125∘ respectively. When thermometer X measures the temperature of a bath as 60∘ on it, what would thermometer Y read when it is used to measure the temperature of the same bath?

A stone tied to the end of a string 100 cm long is whirled in a horizontal circle with a constant speed. If the stone makes 14 revolutions in 22 s, then the acceleration of the stone is:

The image for the converging beam after refraction through the curved surface is formed at

A uniform disc of radius a and mass m, is rotating freely with angular speed ω in a horizontal plane about a smooth ﬁxed vertical axis through its centre. A particle, also of mass m, is suddenly attached to the rim of the disc and rotates with it. The new angular speed is

A horizontal solid cylinder (of mass m) is pivoted about its longitudinal axis. To the end of a thread wrapped on the cylinder a block (of mass 2m) is attached, as shown. If the system is left free, acceleration of the block (in ms−2) is (string is massless and there is no slipping anywhere)

Which of the following graph shows the relation between shear stress and velocity gradient for a non-Newtonian fluid?

A square is made by joining four rods each of mass m and length L each. Its moment of inertia about an axis PQ, on its plane and passing through one of its corners (as shown in the figure) will be:

Match the corresponding entities COLUMN 1. COLUMN 2 (A)m=-2. (a) convex mirror (B)m=-1/2. (b)concave mirror (C)m=2. (c)real image (D)m=+1/2. (d) virtual image Can you pease provide the explanation too.

The kα x-ray emission line of tungsten occurs at λ=0.2 ∘A. If energy difference between K and L level in this atom is approximately (10n) keV, then n is [Take hc = 1200 eV-nm]

Consider the refraction of light ray as shown in the figure below. Incident ray is rotating with constant angular velocity 2 rad/s. What is the angular velocity of refracted ray, when the angle of incidence becomes 30∘? (Given ratio of refractive indices n1n2=√3)

A body is projected vertically upward with speed 40 m/s. The distance travelled by the body in last 2 second of the journey is [g=10 m/s2]

Find the frictional force between the two blocks. Take g=10 m/s2.

The volume of a cube is increasing at the rate of 8cm3/s. How fast is the surface area increasing when the length of an edge is 12 cm?

Two unknown resistances X and Y are connected in left and right gaps of a metre bridge and the balancing point is obtained at 50 cm from left. When a 20 Ω resistance is connected in series with X, the balancing point is at 60 cm from left. The values of X and Y respectively (in ohms) are

In a region, the potential is represented by V(x,y,z)=6x−8xy+6yz, where V is in volts and x, y and z are in metres. The electric force experienced by a charge of 2 Coulomb situated at point (1,1,1) is

Two tuning forks when sounded together produce 6 beats/s. The first fork has the frequency 3% higher than a standard one and the second has the frequency 2% less than the standard fork. The frequencies for the forks are

A particle moves along the path ABCA with a constant speed starting from A. Part BC is circular with centre at A. The magnitude of displacement (from A) versus time graph will be

Do Broglie equation describes the relationship of wavelength associated with the motion of an electron and its

What is ionisation energy?

If we assume that there exists heaven such that 1 year on earth is equal to 1 day on heaven then what could be the possible reason for this phenomenon?

Explain briefly about phasor in angular simple harmonic motion

if a train is moving on the circular path of 1500m radius at the rate of 66km per hour,find the angle in radian,if it has in 10sec

Each division on the main scale of a Vernier callipers is 1mm. Which of the following Vernier scales give the least count equal to 0.01mm ? (A)9 mm divided into 100 divisions (B)99 mm divided into 100 divisions

Three forces are acting on a body in which option can be body in equilibrium A. 2 , 4 , 5 B 1, 2, 3 C 3, 3, 7 D 5, 2, 1

According to Bernoulli's principle ------ as the velocity of an incompressible fluid increases , the pressure reduces . Please explain why this happens

The meter is defined as the distance traveled by light in vacuum in 1/299792458 sec. Why it has been chosen not anything else?

The NOR gate is OR gate followed by

A particle is falling freely under the action of gravity. It covers a distance x1 in the first ′t′ seconds and distance x2 in the next ′t′ seconds, then ′t′ is given by

The velocity and acceleration amplitudes of body executing simple harmonic motion is

Inside the toroid, in which direction does the magnetic field point?

ΔABC is a right angled triangle right angled at B and BD is the altitude from B on side AC. If BD=9 cm and inradii of ΔABC,ΔABD and ΔBCD are r1,r2 and r3 respectively, then r1+r2+r3 is

A simple harmonic oscillator has an amplitude a and time period T. The time required by it to travel from x = a to x = a2 is [CBSE PMT 1992; SCRA 1996; BHU 1997]

Let →a, →b and →c be 3 mutually perpendicular unit vectors. If →d is a unit vector which is equally inclined to →a, →b and →c, then the value of |→a+→b+→c+→d|2 is p+√q then p+q is

If →A.→B=|→A×→B|, find angle between →A and →B.

A 0.10 kg block oscillates back and forth along a horizontal surface. Its displacement from the origin is given by: x=(10cm)cos[(10rads)t+π2rad] . What is the maximum acceleration experienced by the block [AMU (Engg.) 2000]

A caesium photocell, with a steady potential difference of 60V across, is illuminated by a bright point source of light 50 cm away. When the same light is placed 1m away the photoelectrons emitted from the cell

A circular plate of uniform thickness has a diameter of 28 cm. A circular portion of diameter 21 cm is removed from the plate as shown. O is the centre of mass of the complete plate. The position of centre of mass of the remaining portion will shift towards left from O by

A particle of mass 200 gm executes S.H.M. The restoring force is provided by a spring of force constant 80 N / m. The time period of oscillations is.

A ball is thrown vertically upward from the ground. It reaches a maximum height of 20 m in 5 sec. After what time, it will reach the ground from its maximum height position?

Neglecting the air resistance, the time of flight of a projectile is determined by

What is electrostatic potential map and explain it's use

A particle is moving on a circular path with constant speed, then its acceleration will be

Two liquids of the same mass which are at temperatures 20∘C and 40∘C are mixed to form a composite liquid. If the temperature of the mixture is 32∘C, then the ratio of their heat capacities is