50278 + Interview Questions in Physics

1.	A solenoid 1.0 m long and 0.05 m diameter has 700 turns. Another solenoid of 50 turns is tightly wound over the first solenoid. Find the emf induced in the second solenoid when the current in the first solenoid changes from 0 to 5 A in 0.01 s.
Answer» A solenoid $1.0 m$ long and $0.05 m$ diameter has $700$ turns. Another solenoid of 50 turns is tightly wound over the first solenoid. Find the emf induced in the second solenoid when the current in the first solenoid changes from $0$ to $5 A$ in $0.01 s$ .

Discussion

2.	Calculate the heat absorbed by the system undergoing a cyclic process as shown in the figure below.
Answer» Calculate the heat absorbed by the system undergoing a cyclic process as shown in the figure below.

Discussion

3.	Your Results For Why do fluids exert pressure on object present or immersed in it? Where in the world does it get the force from? How is it related to weight if it acts perpendicularly to all faces?
Answer» Your Results For Why do fluids exert pressure on object present or immersed in it? Where in the world does it get the force from? How is it related to weight if it acts perpendicularly to all faces?

Discussion

4.	On a new scale of temperature (which is linear) and called the W scale, the freezing and boiling points of water are 42∘W and 242∘ W respectively. What will be the temperature on the new scale, corresponding to the temperature of 42∘C on the Celsius scale ?
Answer» On a new scale of temperature (which is linear) and called the $W$ scale, the freezing and boiling points of water are $42^{\circ} W$ and $242^{\circ} W$ respectively. What will be the temperature on the new scale, corresponding to the temperature of $42^{\circ} C$ on the Celsius scale ?

Discussion

5.	Show that the semi-vertical angle of the cone of the maximum volume and of given slant height is tan−1√2. Show that the semi-vertical angle of the right circular cone of given surface area and maximum volume is sin−1(13)
Answer» Show that the semi-vertical angle of the cone of the maximum volume and of given slant height is $t a n^{- 1} \sqrt{2}$ . Show that the semi-vertical angle of the right circular cone of given surface area and maximum volume is $s i n^{- 1} (\frac{1}{3})$

5.

Show that the semi-vertical angle of the cone of the maximum volume and of given slant height is tan−1√2. Show that the semi-vertical angle of the right circular cone of given surface area and maximum volume is sin−1(13)

Answer»

Show that the semi-vertical angle of the cone of the maximum volume and of given slant height is $t a n^{- 1} \sqrt{2}$ .

Show that the semi-vertical angle of the right circular cone of given surface area and maximum volume is $s i n^{- 1} (\frac{1}{3})$

Discussion

6.	In the given figure, all the collisions are elastic. Find the velocity of nth ball after collision.
Answer» In the given figure, all the collisions are elastic. Find the velocity of $n^{t h}$ ball after collision.

Discussion

7.	If in a wire of Young's modulus Y, longitudinal strain X is produced, then the potential energy stored in its unit volume will be :
Answer» If in a wire of Young's modulus $Y$ , longitudinal strain $X$ is produced, then the potential energy stored in its unit volume will be :

Discussion

8.	given B=B0sin(kx-wt), what is the magnetic energy density associated with the em wave? and what is the energy density associated with the wave?(is it 2 times the first answer)?
Answer» given B=B₀sin(kx-wt), what is the magnetic energy density associated with the em wave? and what is the energy density associated with the wave?(is it 2 times the first answer)?

Discussion

9.	A ball is thrown from a point with a speed v0 at an angle of projection θ. From the same point and at the same instant a person starts running with a constant speed v02 to catch the ball. Will the person be able to catch the ball? If yes, what should be the angle of projection
Answer» A ball is thrown from a point with a speed $v_{0}$ at an angle of projection $θ$ . From the same point and at the same instant a person starts running with a constant speed $\frac{v_{0}}{2}$ to catch the ball. Will the person be able to catch the ball? If yes, what should be the angle of projection

Discussion

10.	In a capacitance dominated RLC circuit
Answer» In a capacitance dominated RLC circuit

Discussion

11.	A pizza shaped wire carries a current of 5A as shown below. If the angle subtended is π3 radians and its radius is 10 cm, what will be the strength of magnetic field due to it at its centre? (Magnetic field due to straight wire at any point passing through it will be zero)
Answer» A pizza shaped wire carries a current of 5A as shown below. If the angle subtended is $\frac{π}{3}$ radians and its radius is 10 cm, what will be the strength of magnetic field due to it at its centre? (Magnetic field due to straight wire at any point passing through it will be zero)

Discussion

12.	A train has just complicated a U-curve in a track which is a semicircle. The engine is at the forward end of the semi circular part of the track while the last carriage is at the rear end of the semicircular track. The driver blows a whistle of frequency 200 Hz. Velocity of sound is 340 m/sec. Then the apparent frequency as observed by a passenger in the middle of a train when the speed of the train is 30 m/sec is
Answer» A train has just complicated a U-curve in a track which is a semicircle. The engine is at the forward end of the semi circular part of the track while the last carriage is at the rear end of the semicircular track. The driver blows a whistle of frequency 200 Hz. Velocity of sound is 340 m/sec. Then the apparent frequency as observed by a passenger in the middle of a train when the speed of the train is 30 m/sec is

12.

A train has just complicated a U-curve in a track which is a semicircle. The engine is at the forward end of the semi circular part of the track while the last carriage is at the rear end of the semicircular track. The driver blows a whistle of frequency 200 Hz. Velocity of sound is 340 m/sec. Then the apparent frequency as observed by a passenger in the middle of a train when the speed of the train is 30 m/sec is

Answer»

A train has just complicated a U-curve in a track which is a semicircle. The engine is at the forward end of the semi circular part of the track while the last carriage is at the rear end of the semicircular track. The driver blows a whistle of frequency 200 Hz. Velocity of sound is 340 m/sec. Then the apparent frequency as observed by a passenger in the middle of a train when the speed of the train is 30 m/sec is

Discussion

13.	A metre-long tube open at one end, with a movable piston at the other end, shows resonance with a fixed frequency source ( a tunning fork of frequency 340Hz) when the tube length is 25.5cm or 79.3cm. Estimate the speed of sound in air at the temperature of the experiment. The edge effects may be neglected. I saw the solution of the question provided in the website. But I couldn't understand why they assumed it as fundamental mode of vibration without being provided in the question. So please help me to overcome my doubt.
Answer» A metre-long tube open at one end, with a movable piston at the other end, shows resonance with a fixed frequency source ( a tunning fork of frequency 340Hz) when the tube length is 25.5cm or 79.3cm. Estimate the speed of sound in air at the temperature of the experiment. The edge effects may be neglected. I saw the solution of the question provided in the website. But I couldn't understand why they assumed it as fundamental mode of vibration without being provided in the question. So please help me to overcome my doubt.

Discussion

14.	A large open tank has two holes in the wall. One is a square hole of side L at a depth y from the top and the other is a circular hole of radius R at a depth 4y from the top. When the tank is completely filled with water. The quantities of water flowing out per second from both holes are the same. Then, R is equal to
Answer» A large open tank has two holes in the wall. One is a square hole of side L at a depth y from the top and the other is a circular hole of radius R at a depth 4y from the top. When the tank is completely filled with water. The quantities of water flowing out per second from both holes are the same. Then, R is equal to

Discussion

15.	In videos destructive interference is given (2n+ 1)lambda/2 where as in board book it is given by (2n - 1)lambda/2. Which of these is correct for destructive interference?
Answer» In videos destructive interference is given (2n+ 1)lambda/2 where as in board book it is given by (2n - 1)lambda/2. Which of these is correct for destructive interference?

Discussion

16.	What would be the maximum number of emission lines for atomic hydrogen that you would expect to see with the naked eye if the only electronic energy levels involved are those as shown in the Figure?
Answer» What would be the maximum number of emission lines for atomic hydrogen that you would expect to see with the naked eye if the only electronic energy levels involved are those as shown in the Figure?

16.

What would be the maximum number of emission lines for atomic hydrogen that you would expect to see with the naked eye if the only electronic energy levels involved are those as shown in the Figure?

Answer»

What would be the maximum number of emission lines for atomic hydrogen that you would expect to see with the naked eye if the only electronic energy levels involved are those as shown in the Figure?

Discussion

17.	A block is placed on an inclined plane moving horizontally towards right with an acceleration a=g. Take g=10 ms−2 .The length of plane AC =1 m. Friction is absent everywhere. Time taken by the block to reach from C to A is
Answer» A block is placed on an inclined plane moving horizontally towards right with an acceleration $a = g$ . Take $g = 10 {ms}^{- 2}$ .The length of plane $AC = 1 m$ . Friction is absent everywhere. Time taken by the block to reach from $C$ to $A$ is

Discussion

18.	emf is measured in
Answer» emf is measured in

Discussion

19.	When the white light travels through the glass the refractive index of Glass is found to vary with wavelength as Meu= A + B/ lambda square .Using the principle of homeogenity of dimensions find the SI units in which the constants A and B must be expressed
Answer» When the white light travels through the glass the refractive index of Glass is found to vary with wavelength as Meu= A + B/ lambda square .Using the principle of homeogenity of dimensions find the SI units in which the constants A and B must be expressed

Discussion

20.	Figure 3.23 gives the x-t plot of a particle executing one-dimensional simple harmonic motion. (You will learn about this motion in more detail in Chapter14). Give the signs of position, velocity and acceleration variables of the particle at t = 0.3 s, 1.2 s, – 1.2 s.
Answer» Figure 3.23 gives the x-t plot of a particle executing one-dimensional simple harmonic motion. (You will learn about this motion in more detail in Chapter14). Give the signs of position, velocity and acceleration variables of the particle at t = 0.3 s, 1.2 s, – 1.2 s.

Discussion

21.	A concrete sphere of radius R has a cavity of radius r which is packed with sawdust. The relative densities of concrete and sawdust are 2.4 and 0.3 respectively. For this sphere to float with its entire volume submerged under water, the ratio of the mass of concrete to the mass of sawdust will be
Answer» A concrete sphere of radius R has a cavity of radius r which is packed with sawdust. The relative densities of concrete and sawdust are 2.4 and 0.3 respectively. For this sphere to float with its entire volume submerged under water, the ratio of the mass of concrete to the mass of sawdust will be

Discussion

22.	The vector projection of a vector 3^i+4^j on y-axis is
Answer» The vector projection of a vector $3^i + 4^j$ on y-axis is

Discussion

23.	The innermost orbit of the hydrogen atom has a diameter 1.06∘A. The diameter of tenth orbit is
Answer» The innermost orbit of the hydrogen atom has a diameter $1.06 \circ A$ . The diameter of tenth orbit is

Discussion

24.	A body of mass m moving with a speed v suffers an inelastic collision with another body of M at rest and sticks to it. The speed of the composite body will be
Answer» A body of mass m moving with a speed v suffers an inelastic collision with another body of M at rest and sticks to it. The speed of the composite body will be

Discussion

25.	In the x-y-plane, the region y>0 has a uniform magnetic field B1^k and the region y<0 has another uniform magnetic field B2^k. A positively charged particle is projected from the origin along the positive y-axis with speed Vo=πms−1 at t=0, as shown in the figure. Neglect gravity in this problem. Let t=T be the time when the particle crosses the x-axis from below for the first time. If B2=4B1, the average speed of the particle, in ms−1, along the x-axis in the time interval T is
Answer» In the x-y-plane, the region $y > 0$ has a uniform magnetic field $B_{1}^k$ and the region $y < 0$ has another uniform magnetic field $B_{2}^k$ . A positively charged particle is projected from the origin along the positive $y$ -axis with speed $V_{o} = π m s^{- 1}$ at $t = 0$ , as shown in the figure. Neglect gravity in this problem. Let $t = T$ be the time when the particle crosses the x-axis from below for the first time. If $B_{2} = 4 B_{1}$ , the average speed of the particle, in $m s^{- 1}$ , along the x-axis in the time interval $T$ is

Discussion

26.	The figure shows at time t=0 sec, a rectangular and triangular pulse on a uniform wire. They are approaching each other. The pulse speeds are 0.5 cm/s each. The resultant pulse at t=2 sec is
Answer» The figure shows at time $t = 0 sec$ , a rectangular and triangular pulse on a uniform wire. They are approaching each other. The pulse speeds are $0.5 cm/s$ each. The resultant pulse at $t = 2 sec$ is

Discussion

27.	A small object is placed 10 cm in front of a plane mirror. If you stand behind the object 30 cm from the mirror and look at its image, the distance between the observer and the image of the object will be
Answer» A small object is placed $10 cm$ in front of a plane mirror. If you stand behind the object $30 cm$ from the mirror and look at its image, the distance between the observer and the image of the object will be

Discussion

28.	A thin convex lens of focal length 50 cm is cut into two pieces 0.5 cm above the principal axis as shown. The parts are now placed on the x-axis. The x co-ordinate of the image of an object placed at (–100, 0) after refraction at both the parts is
Answer» A thin convex lens of focal length 50 cm is cut into two pieces 0.5 cm above the principal axis as shown. The parts are now placed on the x-axis. The x co-ordinate of the image of an object placed at (–100, 0) after refraction at both the parts is

28.

A thin convex lens of focal length 50 cm is cut into two pieces 0.5 cm above the principal axis as shown. The parts are now placed on the x-axis. The x co-ordinate of the image of an object placed at (–100, 0) after refraction at both the parts is

Answer»

A thin convex lens of focal length 50 cm is cut into two pieces 0.5 cm above the principal axis as shown. The parts are now placed on the x-axis. The x co-ordinate of the image of an object placed at (–100, 0) after refraction at both the parts is

Discussion

29.	In the figure shown, lower pulley is free to move in vertical direction only. Block A is given a uniform velocity u as shown, what is velocity of block B as a function of angle θ.
Answer» In the figure shown, lower pulley is free to move in vertical direction only. Block A is given a uniform velocity u as shown, what is velocity of block B as a function of angle $θ$ .

29.

In the figure shown, lower pulley is free to move in vertical direction only. Block A is given a uniform velocity u as shown, what is velocity of block B as a function of angle θ.

Answer»

In the figure shown, lower pulley is free to move in vertical direction only. Block A is given a uniform velocity u as shown, what is velocity of block B as a function of angle $θ$ .

Discussion

30.	A car starts from rest and accelerates uniformly to a speed of 180 km/h in 10 s. The distance covered by the car in this time interval is
Answer» A car starts from rest and accelerates uniformly to a speed of $180 km/h$ in $10 s$ . The distance covered by the car in this time interval is

Discussion

31.	The radius of gyration of a uniform rod of length l about an axis passing through a point l/4 away from the center of the rod, and perpendicular to it, is
Answer» The radius of gyration of a uniform rod of length $l$ about an axis passing through a point $l / 4$ away from the center of the rod, and perpendicular to it, is

Discussion

32.	Two long parallel wires carrying currents 2.5 A and "I" A in the same direction (directed in the o plane) are held at P and Q respectively as shown. The points P and Q are located at a distance of 5 m and 2 m respectively from a collinear point R. An electron moving with a velocity of 4×105 ms−1 along the positive x-axis experiences a force of magnitude 3.2×10−20 N at the point R. The value of I is
Answer» Two long parallel wires carrying currents 2.5 A and "I" A in the same direction (directed in the o plane) are held at P and Q respectively as shown. The points P and Q are located at a distance of 5 m and 2 m respectively from a collinear point R. An electron moving with a velocity of $4 \times 10^{5} m s^{- 1}$ along the positive x-axis experiences a force of magnitude $3.2 \times 10^{- 20} N$ at the point R. The value of I is

Discussion

33.	A car is moving on a circular level road of radius 300 m. If the coefficient of static friction is 0.3, maximum safe speed (in km/h) of the car can be [Take g=10 m/s2]
Answer» A car is moving on a circular level road of radius $300 m$ . If the coefficient of static friction is $0.3$ , maximum safe speed (in $km/h$ ) of the car can be [Take $g = 10 {m/s}^{2}$ ]

Discussion

34.	From a circular disk of radius (R=50 cm), a square is cut with one of its radii as the diagonal of the square (as shown in figure). The distance of the center of mass of the remaining part from the geometrical center of the disc is
Answer» From a circular disk of radius ( $R = 50 cm$ ), a square is cut with one of its radii as the diagonal of the square (as shown in figure). The distance of the center of mass of the remaining part from the geometrical center of the disc is

Discussion

35.	A conducting loop of face-area A and resistance R is placed perpendicular to a magnetic field B. The loop is withdrawn completely from the field. Find the charge which flows through any cross-section of the wire in the process. Note that it is independent of the shape of the loop as well as the way it is withdrawn.
Answer» A conducting loop of face-area A and resistance R is placed perpendicular to a magnetic field B. The loop is withdrawn completely from the field. Find the charge which flows through any cross-section of the wire in the process. Note that it is independent of the shape of the loop as well as the way it is withdrawn.

Discussion

36.	A body of mass 10 kg is kept on a rough horizontal surface. A force of 50 N is required to just move the body. If the body is cut into two equal parts and placed one over the other, find the force required to just move the body.
Answer» A body of mass $10 kg$ is kept on a rough horizontal surface. A force of $50 N$ is required to just move the body. If the body is cut into two equal parts and placed one over the other, find the force required to just move the body.

Discussion

37.	What is fermi-energy level?
Answer» What is fermi-energy level?

Discussion

38.	Instantaneous temperature difference between a cooling body and the surroundings, obeying Newton's law of cooling, is θ. Which of the following represents the variation of ln θ with time t?
Answer» Instantaneous temperature difference between a cooling body and the surroundings, obeying Newton's law of cooling, is $θ$ . Which of the following represents the variation of ln $θ$ with time $t$ ?

Discussion

39.	In the figure shown, find the velocity of the 3 kg mass after 10 s if the system is released from rest at t=0. (Take g=10 m/s2)
Answer» In the figure shown, find the velocity of the $3 k g$ mass after $10 s$ if the system is released from rest at $t = 0$ . (Take $g = 10 m / s^{2}$ )

Discussion

40.	A plank with mass M=6 kg rests on top of two identical, solid, cylindrical rollers that have radius R=4 cm and mass m=2 kg. The plank is pulled by a constant horizontal force →F of magnitude 6 N applied to the end of the plank and perpendicular to the axes of the cylinders (which are parallel). The cylinders roll without slipping on the flat surface. Also, there is no slipping between the cylinders and the plank. The total friction acting on the plank in newton is (answer upto two decimal places)
Answer» A plank with mass $M = 6 k g$ rests on top of two identical, solid, cylindrical rollers that have radius $R = 4 c m$ and mass $m = 2 k g$ . The plank is pulled by a constant horizontal force $\to F$ of magnitude 6 $N$ applied to the end of the plank and perpendicular to the axes of the cylinders (which are parallel). The cylinders roll without slipping on the flat surface. Also, there is no slipping between the cylinders and the plank. The total friction acting on the plank in newton is (answer upto two decimal places)

Discussion

41.	A coin placed on uniformly rotating turntable just slips if it is placed at a distance of 4 cm from the centre. If the angular velocity of the turntable is doubled, it will just slip at a distance of
Answer» A coin placed on uniformly rotating turntable just slips if it is placed at a distance of 4 cm from the centre. If the angular velocity of the turntable is doubled, it will just slip at a distance of

Discussion

42.	We have the following 2-D crystal arrangement. What will be the mass of the unit cell? Assume each circle has a mass m.
Answer» We have the following 2-D crystal arrangement. What will be the mass of the unit cell? Assume each circle has a mass m.

42.

We have the following 2-D crystal arrangement. What will be the mass of the unit cell? Assume each circle has a mass m.

Answer»

We have the following 2-D crystal arrangement. What will be the mass of the unit cell?

Assume each circle has a mass m.

Discussion

43.	A long uniform beam is acted upon by several forces as shown in figure, and it is in complete equilibrium. What will be the value of forces X & Y? Neglect the mass of the beam.
Answer» A long uniform beam is acted upon by several forces as shown in figure, and it is in complete equilibrium. What will be the value of forces $X & Y$ ? Neglect the mass of the beam.

Discussion

44.	A block of wood floats in water with 45th of its volume submerged but in another liquid, it floats fully submerged. The density of the unknown liquid is (in kg/m3)
Answer» A block of wood floats in water with ${\frac{4}{5}}^{th}$ of its volume submerged but in another liquid, it floats fully submerged. The density of the unknown liquid is (in ${kg/m}^{3}$ )

Discussion

45.	Let An be the area enclosed by nth orbit in a hydrogen atom. The graph of {AnA1} against ln(n)
Answer» Let $A_{n}$ be the area enclosed by nth orbit in a hydrogen atom. The graph of ${\frac{A_{n}}{A_{1}}}$ against ln(n)

Discussion

46.	A single slit diffraction is obtained using a beam of red light. If red light is replaced by blue light, what happens?
Answer» A single slit diffraction is obtained using a beam of red light. If red light is replaced by blue light, what happens?

Discussion

47.	P−V graph for an ideal gas undergoing a polytropic process given by PVn=k is shown below. Find the value of n.
Answer» $P - V$ graph for an ideal gas undergoing a polytropic process given by $P V^{n} = k$ is shown below. Find the value of $n$ .

Discussion

48.	A student measured the diameter of a small steel ball using a screw gauge of least count 0.001 cm. The main scale reading is 5 mm and zero of circular scale division coincides with 25 divisions above the reference level. If screw gauge has a zero error of –0.004 cm, the correct diameter of the ball is
Answer» A student measured the diameter of a small steel ball using a screw gauge of least count $0.001 c m$ . The main scale reading is $5 m m$ and zero of circular scale division coincides with $25$ divisions above the reference level. If screw gauge has a zero error of $- 0.004 c m$ , the correct diameter of the ball is

Discussion

49.	In a Lloyd's single mirror experiment, the distance between the slit source and its image is 5 mm. The screen is at a distance of 1 m from the source. The fringe width is observed to be 0.1 mm. Then the wavelength of light used is
Answer» In a Lloyd's single mirror experiment, the distance between the slit source and its image is $5 m m$ . The screen is at a distance of $1 m$ from the source. The fringe width is observed to be $0.1 m m$ . Then the wavelength of light used is

Discussion

50.	Two concentric metallic shells of radii R and 2R are placed in vacuum. The inner shell is having charge Q and outer shell is uncharged. If they are connected with a conducting wire, Then
Answer» Two concentric metallic shells of radii R and 2R are placed in vacuum. The inner shell is having charge Q and outer shell is uncharged. If they are connected with a conducting wire, Then

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

A solenoid 1.0 m long and 0.05 m diameter has 700 turns. Another solenoid of 50 turns is tightly wound over the first solenoid. Find the emf induced in the second solenoid when the current in the first solenoid changes from 0 to 5 A in 0.01 s.

Calculate the heat absorbed by the system undergoing a cyclic process as shown in the figure below.

Your Results For Why do fluids exert pressure on object present or immersed in it? Where in the world does it get the force from? How is it related to weight if it acts perpendicularly to all faces?

On a new scale of temperature (which is linear) and called the W scale, the freezing and boiling points of water are 42∘W and 242∘ W respectively. What will be the temperature on the new scale, corresponding to the temperature of 42∘C on the Celsius scale ?

Show that the semi-vertical angle of the cone of the maximum volume and of given slant height is tan−1√2. Show that the semi-vertical angle of the right circular cone of given surface area and maximum volume is sin−1(13)

In the given figure, all the collisions are elastic. Find the velocity of nth ball after collision.

If in a wire of Young's modulus Y, longitudinal strain X is produced, then the potential energy stored in its unit volume will be :

given B=B0sin(kx-wt), what is the magnetic energy density associated with the em wave? and what is the energy density associated with the wave?(is it 2 times the first answer)?

A ball is thrown from a point with a speed v0 at an angle of projection θ. From the same point and at the same instant a person starts running with a constant speed v02 to catch the ball. Will the person be able to catch the ball? If yes, what should be the angle of projection

In a capacitance dominated RLC circuit

A pizza shaped wire carries a current of 5A as shown below. If the angle subtended is π3 radians and its radius is 10 cm, what will be the strength of magnetic field due to it at its centre? (Magnetic field due to straight wire at any point passing through it will be zero)

In videos destructive interference is given (2n+ 1)lambda/2 where as in board book it is given by (2n - 1)lambda/2. Which of these is correct for destructive interference?

What would be the maximum number of emission lines for atomic hydrogen that you would expect to see with the naked eye if the only electronic energy levels involved are those as shown in the Figure?

A block is placed on an inclined plane moving horizontally towards right with an acceleration a=g. Take g=10 ms−2 .The length of plane AC =1 m. Friction is absent everywhere. Time taken by the block to reach from C to A is

emf is measured in

When the white light travels through the glass the refractive index of Glass is found to vary with wavelength as Meu= A + B/ lambda square .Using the principle of homeogenity of dimensions find the SI units in which the constants A and B must be expressed

Figure 3.23 gives the x-t plot of a particle executing one-dimensional simple harmonic motion. (You will learn about this motion in more detail in Chapter14). Give the signs of position, velocity and acceleration variables of the particle at t = 0.3 s, 1.2 s, – 1.2 s.

A concrete sphere of radius R has a cavity of radius r which is packed with sawdust. The relative densities of concrete and sawdust are 2.4 and 0.3 respectively. For this sphere to float with its entire volume submerged under water, the ratio of the mass of concrete to the mass of sawdust will be

The vector projection of a vector 3^i+4^j on y-axis is

The innermost orbit of the hydrogen atom has a diameter 1.06∘A. The diameter of tenth orbit is

A body of mass m moving with a speed v suffers an inelastic collision with another body of M at rest and sticks to it. The speed of the composite body will be

The figure shows at time t=0 sec, a rectangular and triangular pulse on a uniform wire. They are approaching each other. The pulse speeds are 0.5 cm/s each. The resultant pulse at t=2 sec is

A small object is placed 10 cm in front of a plane mirror. If you stand behind the object 30 cm from the mirror and look at its image, the distance between the observer and the image of the object will be

A thin convex lens of focal length 50 cm is cut into two pieces 0.5 cm above the principal axis as shown. The parts are now placed on the x-axis. The x co-ordinate of the image of an object placed at (–100, 0) after refraction at both the parts is

In the figure shown, lower pulley is free to move in vertical direction only. Block A is given a uniform velocity u as shown, what is velocity of block B as a function of angle θ.

A car starts from rest and accelerates uniformly to a speed of 180 km/h in 10 s. The distance covered by the car in this time interval is

The radius of gyration of a uniform rod of length l about an axis passing through a point l/4 away from the center of the rod, and perpendicular to it, is

A car is moving on a circular level road of radius 300 m. If the coefficient of static friction is 0.3, maximum safe speed (in km/h) of the car can be [Take g=10 m/s2]

From a circular disk of radius (R=50 cm), a square is cut with one of its radii as the diagonal of the square (as shown in figure). The distance of the center of mass of the remaining part from the geometrical center of the disc is

A body of mass 10 kg is kept on a rough horizontal surface. A force of 50 N is required to just move the body. If the body is cut into two equal parts and placed one over the other, find the force required to just move the body.

What is fermi-energy level?

Instantaneous temperature difference between a cooling body and the surroundings, obeying Newton's law of cooling, is θ. Which of the following represents the variation of ln θ with time t?

In the figure shown, find the velocity of the 3 kg mass after 10 s if the system is released from rest at t=0. (Take g=10 m/s2)

A coin placed on uniformly rotating turntable just slips if it is placed at a distance of 4 cm from the centre. If the angular velocity of the turntable is doubled, it will just slip at a distance of

We have the following 2-D crystal arrangement. What will be the mass of the unit cell? Assume each circle has a mass m.

A long uniform beam is acted upon by several forces as shown in figure, and it is in complete equilibrium. What will be the value of forces X &amp; Y? Neglect the mass of the beam.

A block of wood floats in water with 45th of its volume submerged but in another liquid, it floats fully submerged. The density of the unknown liquid is (in kg/m3)

Let An be the area enclosed by nth orbit in a hydrogen atom. The graph of {AnA1} against ln(n)

A single slit diffraction is obtained using a beam of red light. If red light is replaced by blue light, what happens?

P−V graph for an ideal gas undergoing a polytropic process given by PVn=k is shown below. Find the value of n.

In a Lloyd's single mirror experiment, the distance between the slit source and its image is 5 mm. The screen is at a distance of 1 m from the source. The fringe width is observed to be 0.1 mm. Then the wavelength of light used is

Two concentric metallic shells of radii R and 2R are placed in vacuum. The inner shell is having charge Q and outer shell is uncharged. If they are connected with a conducting wire, Then

A long uniform beam is acted upon by several forces as shown in figure, and it is in complete equilibrium. What will be the value of forces X & Y? Neglect the mass of the beam.