50278 + Interview Questions in Physics

1.	Two wires one of Steel and other of aluminium each of 2 m long and diameter 20 mm are joined end to end and a composite wire of 4 m is formed. What is the tension in the wire producef on a total extension of 0.9 millimetres?
Answer» Two wires one of Steel and other of aluminium each of 2 m long and diameter 20 mm are joined end to end and a composite wire of 4 m is formed. What is the tension in the wire producef on a total extension of 0.9 millimetres?

Discussion

2.	The retarding acceleration of 4 m/s2 due to frictional force stops a block of mass 40 kg moving on a rough horizontal surface. The coefficient of friction between the block and the surface is
Answer» The retarding acceleration of $4 m / s^{2}$ due to frictional force stops a block of mass $40 k g$ moving on a rough horizontal surface. The coefficient of friction between the block and the surface is

Discussion

3.	A cubical block rests on a plane of μ=√3. The angle through which the plane be inclined to the horizontal so that the block just slides down will be
Answer» A cubical block rests on a plane of $μ = \sqrt{3}$ . The angle through which the plane be inclined to the horizontal so that the block just slides down will be

Discussion

4.	Four billiards balls, each of mass 0.5 kg, all are travelling in the same direction on a billiard table, with speeds of 2 m/s, 4 m/s, 8 m/s and 10 m/s. What is the linear momentum of this system?
Answer» Four billiards balls, each of mass 0.5 kg, all are travelling in the same direction on a billiard table, with speeds of 2 m/s, 4 m/s, 8 m/s and 10 m/s. What is the linear momentum of this system?

Discussion

5.	A point particle of mass m, moves along the uniformly rough track PQR as shown in the figure. The coefficient of friction, between the particle and the rough track equals μ. The particle is released from rest, form the point P and it comes to rest a point R. The energies lost by the ball, over the parts PQ and QR of the track, are equal to each other, and no energy is lost when particle changes direction from PQ to QR. The values of the coefficient of friction μ and the distance x (= QR), are respectively close to
Answer» A point particle of mass m, moves along the uniformly rough track PQR as shown in the figure. The coefficient of friction, between the particle and the rough track equals $μ$ . The particle is released from rest, form the point P and it comes to rest a point R. The energies lost by the ball, over the parts PQ and QR of the track, are equal to each other, and no energy is lost when particle changes direction from PQ to QR. The values of the coefficient of friction $μ$ and the distance x (= QR), are respectively close to

Discussion

6.	Two beams of light having intensities I and 4I interfere to produce a fringe pattern on a screen. The phase difference between the beams is π2 at point A and π at point B. Then, the difference between the resultant intensities at A and B is
Answer» Two beams of light having intensities $I$ and $4 I$ interfere to produce a fringe pattern on a screen. The phase difference between the beams is $\frac{π}{2}$ at point $A$ and $π$ at point $B$ . Then, the difference between the resultant intensities at $A$ and $B$ is

Discussion

7.	A capacitor of capacitance C1=1.0μF can with stand a maximum voltage V1=6.0kV. Anothercapacitor of capacitance C2=2.0μF can withstand a maximum voltage V2=4.0kV. If the capacitors are connected in series, the combination can withstand a maximum voltage of
Answer» A capacitor of capacitance $C_{1} = 1.0 μ F$ can with stand a maximum voltage $V_{1} = 6.0 k V$ . Anothercapacitor of capacitance $C_{2} = 2.0 μ F$ can withstand a maximum voltage $V_{2} = 4.0 k V .$ If the capacitors are connected in series, the combination can withstand a maximum voltage of

Discussion

8.	Find the elongation in the spring for the system shown in the figure. (g=10m/s2)
Answer» Find the elongation in the spring for the system shown in the figure. ( $g = 10 m / s^{2}$ )

Discussion

9.	A ball is thrown from ground level of a field with a speed of 12.0 m/s at an angle of 45∘ with the horizontal. At what distance will it hit the field again? Take g = 10.0 m/s2. ___
Answer» A ball is thrown from ground level of a field with a speed of 12.0 m/s at an angle of $45^{\circ}$ with the horizontal. At what distance will it hit the field again? Take g = 10.0 m/ $s^{2}$ . ___

Discussion

10.	A sphere P of mass m and velocity →v undergoes an oblique and perfectly elastic collision with an identical sphere Q initially at rest. The angle θ between the velocities of the spheres after the collision shall be
Answer» A sphere P of mass m and velocity $\to v$ undergoes an oblique and perfectly elastic collision with an identical sphere Q initially at rest. The angle $θ$ between the velocities of the spheres after the collision shall be

Discussion

11.	Four point charges Q, q, Q and q are placed at the corners of a square of side 'a' as shown in the figure. Q q Find the (a) resultant electric force on a charge Q and (b) potential energy of this system.
Answer» Four point charges Q, q, Q and q are placed at the corners of a square of side 'a' as shown in the figure. Q q Find the (a) resultant electric force on a charge Q and (b) potential energy of this system.

Discussion

12.	Refer to the circuit diagram and the corresponding graphs. The current rises when key K is pressed. With R=R1 and L=L1 the rise of current is shown by curve (1), while curve (2) shows the rise of current when R=R2 and L=L2. The maximum current is same for both curves, then :
Answer» Refer to the circuit diagram and the corresponding graphs. The current rises when key $K$ is pressed. With $R = R_{1}$ and $L = L_{1}$ the rise of current is shown by curve (1), while curve (2) shows the rise of current when $R = R_{2}$ and $L = L_{2}$ . The maximum current is same for both curves, then :

Discussion

13.	The rms velocity of gas molecules of a given amount of a gas at 27∘C and 1.0×105N m−2 pressure is 200 m sec−1. If temperature and pressure are respectively 127∘C and 0.5×105 N m−2, the rms velocity will be:
Answer» The rms velocity of gas molecules of a given amount of a gas at $27^{\circ} C$ and $1.0 \times 10^{5} {N m}^{- 2}$ pressure is $200 {m sec}^{- 1}$ . If temperature and pressure are respectively $127^{\circ} C$ and $0.5 \times 10^{5} {N m}^{- 2}$ , the rms velocity will be:

Discussion

14.	A cell is connected between the points A and C of a circular conductor ABCD of centre O with angle =60∘. If B1 and B2 are the magnitudes of the magnetic fields at O due to the currents in ABC and ADC respectively, the ratio B1B2 is
Answer» A cell is connected between the points $A$ and $C$ of a circular conductor $A B C D$ of centre $O$ with angle $= 60^{\circ}$ . If $B_{1}$ and $B_{2}$ are the magnitudes of the magnetic fields at O due to the currents in $A B C$ and ADC respectively, the ratio $\frac{B_{1}}{B_{2}}$ is

Discussion

15.	32P beta - decays to 32S Find the sum of the energy of the antineutrino and the kinetic energy of the β-particle. Neglect the recoil of the daughter nucleus. Atomic mass of 32P=31.974 u and that of 32S=31.972 u
Answer» $^{32} P$ beta - decays to $^{32} S$ Find the sum of the energy of the antineutrino and the kinetic energy of the $β$ -particle. Neglect the recoil of the daughter nucleus. Atomic mass of $^{32} P = 31.974 u$ and that of $^{32} S = 31.972 u$

Discussion

16.	The angular momentum of electron in nth orbit is given by
Answer» The angular momentum of electron in $n^{t h}$ orbit is given by

Discussion

17.	A particle is performing SHM. When the displacement is one half of its amplitude, find what fraction of total energy are the kinetic and potential energies of the particle?
Answer» A particle is performing SHM. When the displacement is one half of its amplitude, find what fraction of total energy are the kinetic and potential energies of the particle?

Discussion

18.	A particle is at rest at a point (4,3,0). Due to an impulse, it gets linear momentum →P=^i+2^j. The angular momentum of the particle about the origin is
Answer» A particle is at rest at a point $(4, 3, 0)$ . Due to an impulse, it gets linear momentum $\to P =^i + 2^j$ . The angular momentum of the particle about the origin is

Discussion

19.	Find the acceleration of a particle placed on the surface of the earth at the equator due to earth's rotation. The diameter of earth = 12800 km and it takes 24 hours for the earth to complete one revolution about its axis.
Answer» Find the acceleration of a particle placed on the surface of the earth at the equator due to earth's rotation. The diameter of earth = 12800 km and it takes 24 hours for the earth to complete one revolution about its axis.

Discussion

20.	Light is incident from air on oil at an angle of 30 degrees after moving through oil one and another medium oil 2 it enters glass and then it enters water. If the refractive indices of Glass and water are 1.5 and 1.3 respectively find the angle which is the Ray makes with normal in water.
Answer» Light is incident from air on oil at an angle of 30 degrees after moving through oil one and another medium oil 2 it enters glass and then it enters water. If the refractive indices of Glass and water are 1.5 and 1.3 respectively find the angle which is the Ray makes with normal in water.

Discussion

21.	Two tangent galvanometers having coils of same radius are connected in series. A current flowing through them produces deflections of 60∘ and 45∘ respectively. Find the ratio of the number of turns in the coils.
Answer» Two tangent galvanometers having coils of same radius are connected in series. A current flowing through them produces deflections of $60^{\circ}$ and $45^{\circ}$ respectively. Find the ratio of the number of turns in the coils.

Discussion

22.	Between the two stations, a train uniformly accelerates from rest at first, then moves with constant velocity and finally decelerates uniformly to come to rest. If the ratio of the time taken is 1:8:1 and the maximum speed attained is 60 km/h, then what is the average speed over the whole journey?
Answer» Between the two stations, a train uniformly accelerates from rest at first, then moves with constant velocity and finally decelerates uniformly to come to rest. If the ratio of the time taken is $1 : 8 : 1$ and the maximum speed attained is $60 km/h$ , then what is the average speed over the whole journey?

Discussion

23.	Why cannot the motion of an electron around the nucleus be determined separately?
Answer» Why cannot the motion of an electron around the nucleus be determined separately?

Discussion

24.	An optical bench has 1.5 m long scale having four equal divisions in each cm. While measuring the focal length of a convex lens, the lens is kept at 75 cm mark of the scale and the object pin is kept at 45 cm mark. The image of the object pin on the other side of the lens overlaps with image pin that is kept at 135 cm mark. In this experiment, the percentage error in the measurement of the focal length of the lens is
Answer» An optical bench has 1.5 $m$ long scale having four equal divisions in each cm. While measuring the focal length of a convex lens, the lens is kept at 75 $c m$ mark of the scale and the object pin is kept at 45 $c m$ mark. The image of the object pin on the other side of the lens overlaps with image pin that is kept at 135 $c m$ mark. In this experiment, the percentage error in the measurement of the focal length of the lens is

Discussion

25.	Find the minimum value of coefficient of friction between the 4 kg block and the surface for the system to be at rest for the figure shown, (Block A=4 kg and block B=3 kg)
Answer» Find the minimum value of coefficient of friction between the $4 kg$ block and the surface for the system to be at rest for the figure shown, (Block $A = 4 kg$ and block $B = 3 kg$ )

Discussion

26.	If velocity of a particle moving along a straight line changes sinusoidally with time as shown in given graph. The average speed over time interval t=0 to t=2(2n−1) second, n being any positive interget, is xπ m/s. Value of x is (Answer upto 2 decimal digits)
Answer» If velocity of a particle moving along a straight line changes sinusoidally with time as shown in given graph. The average speed over time interval $t = 0$ to $t = 2 (2 n - 1)$ second, n being any positive interget, is $\frac{x}{π} m / s$ . Value of $x$ is (Answer upto 2 decimal digits)

Discussion

27.	Which one of the following is paramagnetic?
Answer» Which one of the following is paramagnetic?

Discussion

28.	Consider the circuit shown in figure (32 - E8). Find the current through the 10 Ω resistor when the switch S is (a) open (b) closed. figure (32 - E8)
Answer» Consider the circuit shown in figure (32 - E8). Find the current through the 10 $Ω$ resistor when the switch S is (a) open (b) closed. figure (32 - E8)

28.

Consider the circuit shown in figure (32 - E8). Find the current through the 10 Ω resistor when the switch S is (a) open (b) closed. figure (32 - E8)

Answer»

Consider the circuit shown in figure (32 - E8). Find the current through the 10 $Ω$ resistor when the switch S is (a) open (b) closed.

figure (32 - E8)

Discussion

29.	Two masses M and m are attached to a vertical axis by weightless threads of combined length l. They are set in rotational motion in a horizontal plane about this axis with constant angular velocity ω. If the tensions in the threads are the same during motion, the distance of M from the axis is
Answer» Two masses M and m are attached to a vertical axis by weightless threads of combined length l. They are set in rotational motion in a horizontal plane about this axis with constant angular velocity $ω$ . If the tensions in the threads are the same during motion, the distance of M from the axis is

Discussion

30.	Consider a gravity-free hall in which an experimenter of mass 50 kg is resting on a 5 kg pillow, 8 ft above the floor of the hall. He pushes the pillow down so that it starts falling at a speed of 8 ft/s. The pillow makes a perfectly elastic collision with the floor, rebounds and reaches the experimenter's head. Find the time elapsed in the process.
Answer» Consider a gravity-free hall in which an experimenter of mass 50 kg is resting on a 5 kg pillow, 8 ft above the floor of the hall. He pushes the pillow down so that it starts falling at a speed of 8 ft/s. The pillow makes a perfectly elastic collision with the floor, rebounds and reaches the experimenter's head. Find the time elapsed in the process.

Discussion

31.	An old man and a boy are walking towards each other and a bird is flying over them as shown in the figure. Find the velocity of tree, bird and old man as seen by boy respectively.
Answer» An old man and a boy are walking towards each other and a bird is flying over them as shown in the figure. Find the velocity of tree, bird and old man as seen by boy respectively.

Discussion

32.	A ball initially at rest, is dropped from building of height 10 m to ground as shown in the figure below. If the coefficient of restitution is e=0.7 and after collision, the ball rebounds back up to height h, find the value of h. (Take g=9.8 m/s2)
Answer» A ball initially at rest, is dropped from building of height $10 m$ to ground as shown in the figure below. If the coefficient of restitution is $e = 0.7$ and after collision, the ball rebounds back up to height $h$ , find the value of $h$ . (Take $g = 9.8 {m/s}^{2})$

Discussion

33.	A ball is projected upwards from the top of tower with a velocity 50 ms−1 making angle 30∘ with the horizontal. The height of the tower is 70 m. After how many seconds from the instant of throwing will the ball reach the ground
Answer» A ball is projected upwards from the top of tower with a velocity $50 m s^{- 1}$ making angle $30^{\circ}$ with the horizontal. The height of the tower is 70 m. After how many seconds from the instant of throwing will the ball reach the ground

Discussion

34.	Super conductor
Answer» Super conductor

Discussion

35.	The equation of a wave travelling in a string can be written as y=3 cos π(100 t−x). Its wavelength is [MNR 1985; CPMT 1991; MP PMT 1994, 97; Pb. PET 2004]
Answer» The equation of a wave travelling in a string can be written as $y = 3 c o s π (100 t - x)$ . Its wavelength is [MNR 1985; CPMT 1991; MP PMT 1994, 97; Pb. PET 2004]

Discussion

36.	A plane is revolving around the earth with a speed of 100 km/hr at a constant height from the surface of earth. The change in the velocity as it travels half circle is
Answer» A plane is revolving around the earth with a speed of 100 km/hr at a constant height from the surface of earth. The change in the velocity as it travels half circle is

Discussion

37.	A body is dropped from the top of a tower. During the last second of its fall, it covers 16/25th of the height of the tower. Calculate the height of the tower.
Answer» A body is dropped from the top of a tower. During the last second of its fall, it covers 16/25th of the height of the tower. Calculate the height of the tower.

Discussion

38.	A river is flowing with a speed of 1 km/hr. A swimmer wants to go to point 'C' starting from 'A'. He swims with a speed of 5 km/hr at an angle θ w.r.t the river flow. If AB = BC = 400 m. At what angle with river bank should swimmer swim?
Answer» A river is flowing with a speed of 1 km/hr. A swimmer wants to go to point 'C' starting from 'A'. He swims with a speed of 5 km/hr at an angle $θ$ w.r.t the river flow. If AB = BC = 400 m. At what angle with river bank should swimmer swim?

38.

A river is flowing with a speed of 1 km/hr. A swimmer wants to go to point 'C' starting from 'A'. He swims with a speed of 5 km/hr at an angle θ w.r.t the river flow. If AB = BC = 400 m. At what angle with river bank should swimmer swim?

Answer»

A river is flowing with a speed of 1 km/hr. A swimmer wants to go to point 'C' starting from 'A'. He swims with a speed of 5 km/hr at an angle $θ$ w.r.t the river flow. If AB = BC = 400 m. At what angle with river bank should swimmer swim?

Discussion

39.	A slab of material of dielectric constant K has the same area as that of the plates of a parallel plate capacitor but has the thickness d, where d is the separation between the plates. Find out the expression for its capacitance when the slab is inserted between the plates of the capacitor.
Answer» A slab of material of dielectric constant $K$ has the same area as that of the plates of a parallel plate capacitor but has the thickness $d$ , where $d$ is the separation between the plates. Find out the expression for its capacitance when the slab is inserted between the plates of the capacitor.

Discussion

40.	Derive an expression for s.h.m. using calculas ?
Answer» Derive an expression for s.h.m. using calculas ?

Discussion

41.	A disc of mass m and radius r is rolling purely on rough surface with velocity v. If initially the spring was in natural state, then maximum compression in spring is
Answer» A disc of mass $m$ and radius $r$ is rolling purely on rough surface with velocity $v$ . If initially the spring was in natural state, then maximum compression in spring is

Discussion

42.	A projectile thrown with an initial speed u and angle of projection 15∘ to the horizontal has a range R. If the same projectile is thrown at an angle of 45∘ to the horizontal with speed 2u, its range will be
Answer» A projectile thrown with an initial speed u and angle of projection $15^{\circ}$ to the horizontal has a range R. If the same projectile is thrown at an angle of $45^{\circ}$ to the horizontal with speed 2u, its range will be

Discussion

43.	Why is the proportionality of charge and the potential of it's surface independent of the shape of the conductor?
Answer» Why is the proportionality of charge and the potential of it's surface independent of the shape of the conductor?

Discussion

44.	A particle is moving along a circular path with a constant speed of 10 m/s. Find the magnitude of change in velocity of the particle when it moves through an angle of 60∘ around the centre of the circle.
Answer» A particle is moving along a circular path with a constant speed of $10 m/s$ . Find the magnitude of change in velocity of the particle when it moves through an angle of $60^{\circ}$ around the centre of the circle.

Discussion

45.	If linear density of a rod of length 3 m varies as λ=2+x, then the position of the centre of mass of the rod is
Answer» If linear density of a rod of length 3 m varies as $λ = 2 + x$ , then the position of the centre of mass of the rod is

Discussion

46.	Two bodies of mass 4 kg and 6 kg are attached to the ends of a string passing over a pulley as shown in the figure below. The 4 kg mass is attached to the tabletop by another string. The tension in this string T1 is equal to (take g=10 ms2 )
Answer» Two bodies of mass $4 kg$ and $6 kg$ are attached to the ends of a string passing over a pulley as shown in the figure below. The $4 kg$ mass is attached to the tabletop by another string. The tension in this string $T_{1}$ is equal to (take $g = 10 \frac{m}{s^{2}}$ )

Discussion

47.	The acceleration of a train travelling with speed of 400 m/s as it goes round a curve of radius 160 m, is
Answer» The acceleration of a train travelling with speed of 400 m/s as it goes round a curve of radius 160 m, is

Discussion

48.	A particle moves with simple harmonic motion in a straight line. In first t s, after starting from rest it travels a distance a and in next t s, it travels 2 a in same direction. The time period of the oscillation is found to be nt, then n is
Answer» A particle moves with simple harmonic motion in a straight line. In first $t s$ , after starting from rest it travels a distance $a$ and in next $t s$ , it travels $2 a$ in same direction. The time period of the oscillation is found to be $n t$ , then $n$ is

Discussion

49.	The angles which the vector i^+j^+rt2k^ makes withe X,Y and Z axes respectively are
Answer» The angles which the vector i^+j^+rt2k^ makes withe X,Y and Z axes respectively are

Discussion

50.	A square loop PQRS carrying a current of 6.0 A is placed near a long wire carrying 10 A as shown in figure (35-E10). (a) Show that the magnetic force acting on the part PQ is equal and opposite to that on the part Rs. (b) Find the magnetic force on the square loop.
Answer» A square loop PQRS carrying a current of 6.0 A is placed near a long wire carrying 10 A as shown in figure (35-E10). (a) Show that the magnetic force acting on the part PQ is equal and opposite to that on the part Rs. (b) Find the magnetic force on the square loop.

50.

A square loop PQRS carrying a current of 6.0 A is placed near a long wire carrying 10 A as shown in figure (35-E10). (a) Show that the magnetic force acting on the part PQ is equal and opposite to that on the part Rs. (b) Find the magnetic force on the square loop.

Answer»

A square loop PQRS carrying a current of 6.0 A is placed near a long wire carrying 10 A as shown in figure (35-E10). (a) Show that the magnetic force acting on the part PQ is equal and opposite to that on the part Rs. (b) Find the magnetic force on the square loop.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Two wires one of Steel and other of aluminium each of 2 m long and diameter 20 mm are joined end to end and a composite wire of 4 m is formed. What is the tension in the wire producef on a total extension of 0.9 millimetres?

The retarding acceleration of 4 m/s2 due to frictional force stops a block of mass 40 kg moving on a rough horizontal surface. The coefficient of friction between the block and the surface is

A cubical block rests on a plane of μ=√3. The angle through which the plane be inclined to the horizontal so that the block just slides down will be

Four billiards balls, each of mass 0.5 kg, all are travelling in the same direction on a billiard table, with speeds of 2 m/s, 4 m/s, 8 m/s and 10 m/s. What is the linear momentum of this system?

Two beams of light having intensities I and 4I interfere to produce a fringe pattern on a screen. The phase difference between the beams is π2 at point A and π at point B. Then, the difference between the resultant intensities at A and B is

A capacitor of capacitance C1=1.0μF can with stand a maximum voltage V1=6.0kV. Anothercapacitor of capacitance C2=2.0μF can withstand a maximum voltage V2=4.0kV. If the capacitors are connected in series, the combination can withstand a maximum voltage of

Find the elongation in the spring for the system shown in the figure. (g=10m/s2)

A ball is thrown from ground level of a field with a speed of 12.0 m/s at an angle of 45∘ with the horizontal. At what distance will it hit the field again? Take g = 10.0 m/s2. ___

A sphere P of mass m and velocity →v undergoes an oblique and perfectly elastic collision with an identical sphere Q initially at rest. The angle θ between the velocities of the spheres after the collision shall be

Four point charges Q, q, Q and q are placed at the corners of a square of side 'a' as shown in the figure. Q q Find the (a) resultant electric force on a charge Q and (b) potential energy of this system.

Refer to the circuit diagram and the corresponding graphs. The current rises when key K is pressed. With R=R1 and L=L1 the rise of current is shown by curve (1), while curve (2) shows the rise of current when R=R2 and L=L2. The maximum current is same for both curves, then :

The rms velocity of gas molecules of a given amount of a gas at 27∘C and 1.0×105N m−2 pressure is 200 m sec−1. If temperature and pressure are respectively 127∘C and 0.5×105 N m−2, the rms velocity will be:

A cell is connected between the points A and C of a circular conductor ABCD of centre O with angle =60∘. If B1 and B2 are the magnitudes of the magnetic fields at O due to the currents in ABC and ADC respectively, the ratio B1B2 is

32P beta - decays to 32S Find the sum of the energy of the antineutrino and the kinetic energy of the β-particle. Neglect the recoil of the daughter nucleus. Atomic mass of 32P=31.974 u and that of 32S=31.972 u

The angular momentum of electron in nth orbit is given by

A particle is performing SHM. When the displacement is one half of its amplitude, find what fraction of total energy are the kinetic and potential energies of the particle?

A particle is at rest at a point (4,3,0). Due to an impulse, it gets linear momentum →P=^i+2^j. The angular momentum of the particle about the origin is

Find the acceleration of a particle placed on the surface of the earth at the equator due to earth's rotation. The diameter of earth = 12800 km and it takes 24 hours for the earth to complete one revolution about its axis.

Light is incident from air on oil at an angle of 30 degrees after moving through oil one and another medium oil 2 it enters glass and then it enters water. If the refractive indices of Glass and water are 1.5 and 1.3 respectively find the angle which is the Ray makes with normal in water.

Two tangent galvanometers having coils of same radius are connected in series. A current flowing through them produces deflections of 60∘ and 45∘ respectively. Find the ratio of the number of turns in the coils.

Between the two stations, a train uniformly accelerates from rest at first, then moves with constant velocity and finally decelerates uniformly to come to rest. If the ratio of the time taken is 1:8:1 and the maximum speed attained is 60 km/h, then what is the average speed over the whole journey?

Why cannot the motion of an electron around the nucleus be determined separately?

Find the minimum value of coefficient of friction between the 4 kg block and the surface for the system to be at rest for the figure shown, (Block A=4 kg and block B=3 kg)

If velocity of a particle moving along a straight line changes sinusoidally with time as shown in given graph. The average speed over time interval t=0 to t=2(2n−1) second, n being any positive interget, is xπ m/s. Value of x is (Answer upto 2 decimal digits)

Which one of the following is paramagnetic?

Consider the circuit shown in figure (32 - E8). Find the current through the 10 Ω resistor when the switch S is (a) open (b) closed. figure (32 - E8)

Two masses M and m are attached to a vertical axis by weightless threads of combined length l. They are set in rotational motion in a horizontal plane about this axis with constant angular velocity ω. If the tensions in the threads are the same during motion, the distance of M from the axis is

An old man and a boy are walking towards each other and a bird is flying over them as shown in the figure. Find the velocity of tree, bird and old man as seen by boy respectively.

A ball initially at rest, is dropped from building of height 10 m to ground as shown in the figure below. If the coefficient of restitution is e=0.7 and after collision, the ball rebounds back up to height h, find the value of h. (Take g=9.8 m/s2)

A ball is projected upwards from the top of tower with a velocity 50 ms−1 making angle 30∘ with the horizontal. The height of the tower is 70 m. After how many seconds from the instant of throwing will the ball reach the ground

Super conductor

The equation of a wave travelling in a string can be written as y=3 cos π(100 t−x). Its wavelength is [MNR 1985; CPMT 1991; MP PMT 1994, 97; Pb. PET 2004]

A plane is revolving around the earth with a speed of 100 km/hr at a constant height from the surface of earth. The change in the velocity as it travels half circle is

A body is dropped from the top of a tower. During the last second of its fall, it covers 16/25th of the height of the tower. Calculate the height of the tower.

A river is flowing with a speed of 1 km/hr. A swimmer wants to go to point 'C' starting from 'A'. He swims with a speed of 5 km/hr at an angle θ w.r.t the river flow. If AB = BC = 400 m. At what angle with river bank should swimmer swim?

A slab of material of dielectric constant K has the same area as that of the plates of a parallel plate capacitor but has the thickness d, where d is the separation between the plates. Find out the expression for its capacitance when the slab is inserted between the plates of the capacitor.

Derive an expression for s.h.m. using calculas ?

A disc of mass m and radius r is rolling purely on rough surface with velocity v. If initially the spring was in natural state, then maximum compression in spring is

A projectile thrown with an initial speed u and angle of projection 15∘ to the horizontal has a range R. If the same projectile is thrown at an angle of 45∘ to the horizontal with speed 2u, its range will be

Why is the proportionality of charge and the potential of it's surface independent of the shape of the conductor?

A particle is moving along a circular path with a constant speed of 10 m/s. Find the magnitude of change in velocity of the particle when it moves through an angle of 60∘ around the centre of the circle.

If linear density of a rod of length 3 m varies as λ=2+x, then the position of the centre of mass of the rod is

Two bodies of mass 4 kg and 6 kg are attached to the ends of a string passing over a pulley as shown in the figure below. The 4 kg mass is attached to the tabletop by another string. The tension in this string T1 is equal to (take g=10 ms2 )

The acceleration of a train travelling with speed of 400 m/s as it goes round a curve of radius 160 m, is

A particle moves with simple harmonic motion in a straight line. In first t s, after starting from rest it travels a distance a and in next t s, it travels 2 a in same direction. The time period of the oscillation is found to be nt, then n is

The angles which the vector i^+j^+rt2k^ makes withe X,Y and Z axes respectively are

A square loop PQRS carrying a current of 6.0 A is placed near a long wire carrying 10 A as shown in figure (35-E10). (a) Show that the magnetic force acting on the part PQ is equal and opposite to that on the part Rs. (b) Find the magnetic force on the square loop.