50278 + Interview Questions in Physics

1.	A small block of mass 1 kg is placed over a plank of mass 2 kg. The length of the plank is 2 m. Coefficient of friction between the block and the plank is 0.5 and the ground over which plank is placed is smooth. A constant force F=30 N is applied on the plank in horizontal direction. The time after which the block will separate from the plank is (g=10 m/s2) approximately
Answer» A small block of mass $1 kg$ is placed over a plank of mass $2 kg$ . The length of the plank is $2 m$ . Coefficient of friction between the block and the plank is $0.5$ and the ground over which plank is placed is smooth. A constant force $F = 30 N$ is applied on the plank in horizontal direction. The time after which the block will separate from the plank is $(g = 10 {m/s}^{2})$ approximately

Discussion

2.	Why potential barrier increases on increase temperature?
Answer» Why potential barrier increases on increase temperature?

Discussion

3.	5. Two masses m1 and m2 are at infinite distance apart and initially at rest .What is their relative velocity of approach when the separation between them is r?
Answer» 5. Two masses m1 and m2 are at infinite distance apart and initially at rest .What is their relative velocity of approach when the separation between them is r?

Discussion

4.	rain is falling with speed 4m/s in in direction making angle 30 degrees with vertical towards north. What should be magnitude and direction of velocity of cyclist to hold his umbrella exactly vertical so that rain does not wet him?
Answer» rain is falling with speed 4m/s in in direction making angle 30 degrees with vertical towards north. What should be magnitude and direction of velocity of cyclist to hold his umbrella exactly vertical so that rain does not wet him?

Discussion

5.	Two spheres of mass 2 kg and 6 kg are moving with velocities 4 m/s and 8 m/s away from each other along the same line. The ball of mass 2 kg is moving towards left. The velocity of the center of mass is
Answer» Two spheres of mass $2 kg$ and $6 kg$ are moving with velocities $4 m/s$ and $8 m/s$ away from each other along the same line. The ball of mass $2 kg$ is moving towards left. The velocity of the center of mass is

Discussion

6.	In a circuit, the reactance X and resistance R are equal. What is the power factor?
Answer» In a circuit, the reactance X and resistance R are equal. What is the power factor?

Discussion

7.	The phase of a particle in SHM at time t is pi/6. The following interference is drawn from this :- (1) The particle is at x = a/2 and moving in +X direction (2) The particle is at x = a/2 and moving in -X direction (3) The particle is at x = -a/2 and moving in +X direction (4) The particle is at x = -a/2 and moving in -X direction
Answer» The phase of a particle in SHM at time t is pi/6. The following interference is drawn from this :- (1) The particle is at x = a/2 and moving in +X direction (2) The particle is at x = a/2 and moving in -X direction (3) The particle is at x = -a/2 and moving in +X direction (4) The particle is at x = -a/2 and moving in -X direction

Discussion

8.	nta flywheel of moment of inertia 2kgm/s square is rotated at a speed of 30rad/s. a tangential force at the rim stops the wheel in 15seconds . Average torque of the force is??n
Answer» nta flywheel of moment of inertia 2kgm/s square is rotated at a speed of 30rad/s. a tangential force at the rim stops the wheel in 15seconds . Average torque of the force is??n

Discussion

9.	128.By which method angle between vectors are calculated
Answer» 128.By which method angle between vectors are calculated

Discussion

10.	A body is projected at t=0 with a velocity 10 ms−1 at an angle 60∘ with the horizontal. The radius of curvature of its trajectory at t=1 is R. Neglecting air resisteance and taking acceleration due to gravity g=10 m/s2, the value of R is:
Answer» A body is projected at $t = 0$ with a velocity $10 {ms}^{- 1}$ at an angle $60^{\circ}$ with the horizontal. The radius of curvature of its trajectory at $t = 1$ is $R$ . Neglecting air resisteance and taking acceleration due to gravity $g = 10 {m/s}^{2}$ , the value of $R$ is:

Discussion

11.	What is the equivalent spring constant for the syatem shown below in the figure?
Answer» What is the equivalent spring constant for the syatem shown below in the figure?

Discussion

12.	The given figure represents the phasor diagram of a series LCR circuit connected to an AC source. At instant t when the source voltage is given by V=V0cosωt, the current in the circuit in terms of peak current I0 will beGiven:VOR=√3 V = Voltage Across ResistorVOL=3 V = Voltage Across Inductor VOC=2 V = Voltage Across capacitor
Answer» The given figure represents the phasor diagram of a series $L C R$ circuit connected to an $A C$ source. At instant $t$ when the source voltage is given by $V = V_{0} cos ω t$ , the current in the circuit in terms of peak current $I_{0}$ will be Given: $V_{O R} = \sqrt{3} V$ = Voltage Across Resistor $V_{O L} = 3 V$ = Voltage Across Inductor $V_{O C} = 2 V$ = Voltage Across capacitor

Discussion

13.	For an electron revolving in the atom, the magnetic dipole moment is given by,
Answer» For an electron revolving in the atom, the magnetic dipole moment is given by,

Discussion

14.	A scooter travelling at 10 m/s speed up to 20 m/s in 4 sec. Find the average acceleration of scooter.
Answer» A scooter travelling at $10 m/s$ speed up to $20 m/s$ in $4 sec$ . Find the average acceleration of scooter.

Discussion

15.	Maximum electric field on axis of a uniformly charged ring of charge q and radius r will be 014 = πε k(1)23 3kqr(2)223kqr(3)223 3kqr(4)2
Answer» Maximum electric field on axis of a uniformly charged ring of charge q and radius r will be 0 1 4   =   πε   k (1) 2 3 3 kq r (2) 2 2 3 kq r (3) 2 2 3 3 kq r (4) 2

Discussion

16.	Define intensity of radiation on the basis of photon picture of light. Write its S.I. unit
Answer» Define intensity of radiation on the basis of photon picture of light. Write its S.I. unit

Discussion

17.	A proton and an electron are placed in uniform electric field. What is the ratio of magnitudes of forces acting on them? What is e forces relative to the direction of electric field in each case?
Answer» A proton and an electron are placed in uniform electric field. What is the ratio of magnitudes of forces acting on them? What is e forces relative to the direction of electric field in each case?

Discussion

18.	A body of mass m hangs from a smooth fixed pulley P1 by an inextensible string fitted with the springs of stiffness constants k1 and k3 The string passes over a smooth light pulley P2 , which is connected with another ideal spring of stiffness constant k2. Find the period of small oscillations of the body.
Answer» A body of mass $m$ hangs from a smooth fixed pulley $P_{1}$ by an inextensible string fitted with the springs of stiffness constants $k_{1}$ and $k_{3}$ The string passes over a smooth light pulley $P_{2}$ , which is connected with another ideal spring of stiffness constant $k_{2}$ . Find the period of small oscillations of the body.

Discussion

19.	The closest distance of approach of an α− particle travelling with a velocity v towards Al(Z=13) nucleus is d. The closest distance of approach of an α−particle travelling with velocity 4v towards Fe(Z=26) nucleus is-
Answer» The closest distance of approach of an $α -$ particle travelling with a velocity $v$ towards $Al (Z = 13)$ nucleus is $d$ . The closest distance of approach of an $α -$ particle travelling with velocity $4 v$ towards $Fe (Z = 26)$ nucleus is-

Discussion

20.	A particle executes SHM with a time period of 8 s. Find the time taken by the particle to go directly from its mean position to half of its amplitude.
Answer» A particle executes SHM with a time period of $8 s$ . Find the time taken by the particle to go directly from its mean position to half of its amplitude.

Discussion

21.	16.Sec40+Sec80+Sec160=?
Answer» 16.Sec40+Sec80+Sec160=?

Discussion

22.	At a certain point in a strained material, the intensities of stresses on two mutually perpendicular planes are 150 N/mm2 (tensile) and 70 N/mm2 (tensile). If the maximum shear stress is 60 N/mm2. The shear stress on these planes will be nearly
Answer» At a certain point in a strained material, the intensities of stresses on two mutually perpendicular planes are $150 N / m m^{2}$ (tensile) and $70 N / m m^{2}$ (tensile). If the maximum shear stress is $60 N / m m^{2}$ . The shear stress on these planes will be nearly

Discussion

23.	A student performs an experiment to determine the Young’s modulus of a wire, exactly 2 m long, by Searle’s method. In a particular reading, the students measures the extension in the length of the wire to be 0.8 mm with an uncertainty of +/- 0.05 mm at a load of exactly 1kg. The student also measures the diameter of the wire to be 0.4 mm with an uncertainty of +/-0.01 mm.The Young’s modulus obtained from the reading is (g= 9.8 ms−2)
Answer» A student performs an experiment to determine the Young’s modulus of a wire, exactly 2 m long, by Searle’s method. In a particular reading, the students measures the extension in the length of the wire to be 0.8 mm with an uncertainty of +/- 0.05 mm at a load of exactly 1kg. The student also measures the diameter of the wire to be 0.4 mm with an uncertainty of +/-0.01 mm.The Young’s modulus obtained from the reading is $(g = 9.8 m s^{- 2})$

Discussion

24.	nitrogen gas is filled in an insulated container if alpha fraction of moles dissociated without exchane of any energy then the fractional change in is temperature is
Answer» nitrogen gas is filled in an insulated container if alpha fraction of moles dissociated without exchane of any energy then the fractional change in is temperature is

Discussion

25.	A difference of 2.3 eV separates two energy levels in an atom. Whatis the frequency of radiation emitted when the atom make atransition from the upper level to the lower level?
Answer» A difference of 2.3 eV separates two energy levels in an atom. Whatis the frequency of radiation emitted when the atom make atransition from the upper level to the lower level?

Discussion

26.	Heat is supplied to a diatomic gas at constant pressure.The ratio of ΔQ:ΔU:ΔW is
Answer» Heat is supplied to a diatomic gas at constant pressure. The ratio of $Δ Q : Δ U : Δ W$ is

Discussion

27.	Define electricity
Answer» Define electricity

Discussion

28.	TV waves have a wavelength range of 1-10 meter. Their frequency range in MHz is
Answer» TV waves have a wavelength range of 1-10 meter. Their frequency range in MHz is

Discussion

29.	In a series LCR circuit, R=200 Ω and the voltage and the frequency of the main supply is 220 V and 50 Hz respectively. On taking out the capacitance from the circuit, the current lags behind the voltage by 30∘. On taking out the inductor from the circuit, the current leads the voltage by 30∘. The power dissipated in the LCR circuit is-
Answer» In a series $L C R$ circuit, $R = 200 Ω$ and the voltage and the frequency of the main supply is $220 V$ and $50 Hz$ respectively. On taking out the capacitance from the circuit, the current lags behind the voltage by $30^{\circ}$ . On taking out the inductor from the circuit, the current leads the voltage by $30^{\circ}$ . The power dissipated in the $L C R$ circuit is-

Discussion

30.	The value of integral ∫dx(x+2)√x+1 is (where C is integration constant)
Answer» The value of integral $\int \frac{d x}{(x + 2) \sqrt{x + 1}}$ is (where $C$ is integration constant)

Discussion

31.	In the earth-moon system, if T1 and T2 are period of revolution of earth and moon respectively about the centre of mass of the system then
Answer» In the earth-moon system, if $T_{1}$ and $T_{2}$ are period of revolution of earth and moon respectively about the centre of mass of the system then

Discussion

32.	Two mirrors are inclined at an angle θ. For an object placed in front of them, 11 images are noticed. Find the angle between the mirrors.
Answer» Two mirrors are inclined at an angle $θ$ . For an object placed in front of them, $11$ images are noticed. Find the angle between the mirrors.

Discussion

33.	From the top of a tower, a particle is thrown vertically downwards with a velocity of 10 m/s. The ratio of distances covered by it in the 3rd and 2nd seconds of its motion is (Take g=10 m/s2)
Answer» From the top of a tower, a particle is thrown vertically downwards with a velocity of $10 m / s$ . The ratio of distances covered by it in the $3^{r d}$ and $2^{n d}$ seconds of its motion is (Take $g = 10 m / s^{2}$ )

Discussion

34.	.A disc revolves in horizontal plane at a steady rate of 3 rev/s. A coin just remains on the disc if kept at a distance of 2 cm from the axis of rotation.What is the coefficient of friction between thecoin and the disc(A) 0-5(C) 0-7(B) 0-65(D) 0-75.
Answer» .A disc revolves in horizontal plane at a steady rate of 3 rev/s. A coin just remains on the disc if kept at a distance of 2 cm from the axis of rotation.What is the coefficient of friction between thecoin and the disc(A) 0-5(C) 0-7(B) 0-65(D) 0-75.

Discussion

35.	If →a=^i+2^j+4^k, →b=^i+λ^j+4^k, →c=2^i+4^j+(λ2−1)^k, are coplanar vectors and →a,→c are not parallel, then \|→a×→c\| is equal to
Answer» If $\to a =^i + 2^j + 4^k, \to b =^i + λ^j + 4^k, \to c = 2^i + 4^j + (λ^{2} - 1)^k,$ are coplanar vectors and $\to a, \to c$ are not parallel, then $\| \to a \times \to c \|$ is equal to

Discussion

36.	A Proton and electron are placed 1.6 CM apart in free space find the magnitude of electrostatic force between them and the nature of the force
Answer» A Proton and electron are placed 1.6 CM apart in free space find the magnitude of electrostatic force between them and the nature of the force

Discussion

37.	Water in a bucket is whirled in a vertical circle with a string attached to it. The water does not fall down even when the bucket is inverted at the top of its path. We conclude that in this position.
Answer» Water in a bucket is whirled in a vertical circle with a string attached to it. The water does not fall down even when the bucket is inverted at the top of its path. We conclude that in this position.

Discussion

38.	There is a small source of light at some depth below the surface of water (refractive index=43), in a tank of large cross-sectional surface area. Neglecting any reflection from the bottom and absorption by water, the percentage of light that emerges out of the surface is (nearly):[use the fact that surface area of a spherical cap of height h and radius of curvature r is 2πrh]
Answer» There is a small source of light at some depth below the surface of water $(refractive index=43)$ , in a tank of large cross-sectional surface area. Neglecting any reflection from the bottom and absorption by water, the percentage of light that emerges out of the surface is (nearly): [use the fact that surface area of a spherical cap of height $h$ and radius of curvature $r$ is $2 π r h$ ]

Discussion

39.	An arc lamp requires a direct current of 10 A at 80 V to function. If it is connected to a 220 V(rms), 50 Hz supply, the series inductor needed for it to work, is close to-
Answer» An arc lamp requires a direct current of $10 A$ at $80 V$ to function. If it is connected to a $220 V (rms)$ , $50 Hz$ supply, the series inductor needed for it to work, is close to-

Discussion

40.	A rigid wire loop of square shape having side of length L and resistance R is moving along the x-axis with a constant velocity v0 in the plane of the paper. At t=0, the right edge of the loop enters a region of length 3L where there is a uniform magnetic field B0 into the plane of the paper, as shown in the figure. For sufficient large v0, the loop eventually crosses the region. Let x be the location of the right edge of the loop. Let v(x),I(x) and F(x) represent the velocity of the loop, current in the loop, and force on the loop, respectively, as a function of x. Counter-clockwise current is taken as positive.Which of the following schematic plot(s) is (are) correct? (Ignore gravity)
Answer» A rigid wire loop of square shape having side of length $L$ and resistance $R$ is moving along the $x$ -axis with a constant velocity $v_{0}$ in the plane of the paper. At $t = 0$ , the right edge of the loop enters a region of length $3 L$ where there is a uniform magnetic field $B_{0}$ into the plane of the paper, as shown in the figure. For sufficient large $v_{0}$ , the loop eventually crosses the region. Let $x$ be the location of the right edge of the loop. Let $v (x), I (x)$ and $F (x)$ represent the velocity of the loop, current in the loop, and force on the loop, respectively, as a function of $x$ . Counter-clockwise current is taken as positive. Which of the following schematic plot(s) is (are) correct? (Ignore gravity)

Discussion

41.	Find the net force acting on pulley 2 assuming all strings and pulleys to be of negligible mass and all surfaces to be frictionless. g=10 m/s2.
Answer» Find the net force acting on pulley $2$ assuming all strings and pulleys to be of negligible mass and all surfaces to be frictionless. $g = 10 {m/s}^{2}$ .

Discussion

42.	A wheel of radius R and mass M is placed at the bottom of a fixed step of height R as shown in the figure. A constant force is continuously applied on the surface of the wheel so that it just climbs the step without slipping. Consider the torque τ about an axis normal to the plane of the paper passing through the point Q. Which of the following options is/are correct?
Answer» A wheel of radius $R$ and mass $M$ is placed at the bottom of a fixed step of height $R$ as shown in the figure. A constant force is continuously applied on the surface of the wheel so that it just climbs the step without slipping. Consider the torque $τ$ about an axis normal to the plane of the paper passing through the point $Q$ . Which of the following options is/are correct?

Discussion

43.	Two cars A and B move on a straight road with constant velocity. When they move in same direction, they come close by 8 m in 10 s and when they move in opposite direction towards each other, they come close by 20 m in 1 s. The speed of the cars A and B (in m/s) respectively are
Answer» Two cars $A$ and $B$ move on a straight road with constant velocity. When they move in same direction, they come close by $8 m$ in $10 s$ and when they move in opposite direction towards each other, they come close by $20 m in 1 s$ . The speed of the cars A and B (in $m / s$ ) respectively are

Discussion

44.	Equation of a progressive wave is given by y=0.2cos π(0.04t+0.02x−π6) where distances are in cm and time in s. What will be the minimum distance between two particles having phase difference of π2?
Answer» Equation of a progressive wave is given by $y = 0.2 cos π (0.04 t + 0.02 x - \frac{π}{6})$ where distances are in $cm$ and time in $s$ . What will be the minimum distance between two particles having phase difference of $\frac{π}{2}$ ?

Discussion

45.	Three tuning forks of frequencies 500 Hz, 501 Hz and 502 Hz respectively are vibrated simul†an eously. The beat frequency heard will be Options: a-Zero b-1 Hz c-2 Hz d- 3 Hz
Answer» Three tuning forks of frequencies 500 Hz, 501 Hz and 502 Hz respectively are vibrated simul†an eously. The beat frequency heard will be Options: a-Zero b-1 Hz c-2 Hz d- 3 Hz

Discussion

46.	A circular plate of radius r is placed on a principal axis at distance from a convex mirror of focal length f' . Such that the Principal axis passes through centre of plate normally. The are of image of the plate is .
Answer» A circular plate of radius r is placed on a principal axis at distance from a convex mirror of focal length f' . Such that the Principal axis passes through centre of plate normally. The are of image of the plate is .

Discussion

47.	Force required to pull a rectangular plate of length 2 cm and breadth 3 cm from water surface for which surface tension is 75 dyne/cm is
Answer» Force required to pull a rectangular plate of length $2 cm$ and breadth $3 cm$ from water surface for which surface tension is $75 dyne/cm$ is

Discussion

48.	Two parallel plates 6 m apart are kept together by a steel rod of 25 mm diameter at a temperature of 78∘C. If the plates do not yield then the pull exerted by the rod when it is cooled to 24∘C is kN. The modulus of elasticity and coefficient of thermal expansion of steel are 200 GPa and 11×10−6 per ∘C respectively.58.32
Answer» Two parallel plates 6 m apart are kept together by a steel rod of 25 mm diameter at a temperature of $78^{\circ} C$ . If the plates do not yield then the pull exerted by the rod when it is cooled to $24^{\circ} C$ is kN. The modulus of elasticity and coefficient of thermal expansion of steel are 200 GPa and $11 \times 10^{- 6}$ per $^{\circ} C$ respectively. 58.32

48.

Two parallel plates 6 m apart are kept together by a steel rod of 25 mm diameter at a temperature of 78∘C. If the plates do not yield then the pull exerted by the rod when it is cooled to 24∘C is kN. The modulus of elasticity and coefficient of thermal expansion of steel are 200 GPa and 11×10−6 per ∘C respectively.58.32

Answer»

Two parallel plates 6 m apart are kept together by a steel rod of 25 mm diameter at a temperature of $78^{\circ} C$ . If the plates do not yield then the pull exerted by the rod when it is cooled to $24^{\circ} C$ is kN. The modulus of elasticity and coefficient of thermal expansion of steel are 200 GPa and $11 \times 10^{- 6}$ per $^{\circ} C$ respectively.

58.32

Discussion

49.	The coil of a galvanometer consists of 100 turns and effective area of 1 cm^2 2. The restoring couple is 10^{-8} Nmrad^-. The magnetic field between poles is of 5T. Current sensitivity of this galvanometer is (1) 5 x 10^4 rad/μ amp (2)5 x 10^6 per amp(3)2 x 10^7 per amp(4) 5 rad/μ amp. Which one is correct between (2) and (4)
Answer» The coil of a galvanometer consists of 100 turns and effective area of 1 cm^2 2. The restoring couple is 10^{-8} Nmrad^-. The magnetic field between poles is of 5T. Current sensitivity of this galvanometer is (1) 5 x 10^4 rad/μ amp (2)5 x 10^6 per amp(3)2 x 10^7 per amp(4) 5 rad/μ amp. Which one is correct between (2) and (4)

Discussion

50.	A ball of mass m is initially at rest. A variable force starts acting on it in a fixed direction, whose magnitude changes with time. The force - time graph is shown in the figure.Find the speed of the ball at the end of time t=T seconds.
Answer» A ball of mass $m$ is initially at rest. A variable force starts acting on it in a fixed direction, whose magnitude changes with time. The force - time graph is shown in the figure. Find the speed of the ball at the end of time $t = T$ seconds.

Discussion

Explore topic-wise InterviewSolutions in Current Affairs.

Why potential barrier increases on increase temperature?

5. Two masses m1 and m2 are at infinite distance apart and initially at rest .What is their relative velocity of approach when the separation between them is r?

rain is falling with speed 4m/s in in direction making angle 30 degrees with vertical towards north. What should be magnitude and direction of velocity of cyclist to hold his umbrella exactly vertical so that rain does not wet him?

Two spheres of mass 2 kg and 6 kg are moving with velocities 4 m/s and 8 m/s away from each other along the same line. The ball of mass 2 kg is moving towards left. The velocity of the center of mass is

In a circuit, the reactance X and resistance R are equal. What is the power factor?

nta flywheel of moment of inertia 2kgm/s square is rotated at a speed of 30rad/s. a tangential force at the rim stops the wheel in 15seconds . Average torque of the force is??n

128.By which method angle between vectors are calculated

A body is projected at t=0 with a velocity 10 ms−1 at an angle 60∘ with the horizontal. The radius of curvature of its trajectory at t=1 is R. Neglecting air resisteance and taking acceleration due to gravity g=10 m/s2, the value of R is:

What is the equivalent spring constant for the syatem shown below in the figure?

For an electron revolving in the atom, the magnetic dipole moment is given by,

A scooter travelling at 10 m/s speed up to 20 m/s in 4 sec. Find the average acceleration of scooter.

Maximum electric field on axis of a uniformly charged ring of charge q and radius r will be 014 = πε k(1)23 3kqr(2)223kqr(3)223 3kqr(4)2

Define intensity of radiation on the basis of photon picture of light. Write its S.I. unit

A proton and an electron are placed in uniform electric field. What is the ratio of magnitudes of forces acting on them? What is e forces relative to the direction of electric field in each case?

The closest distance of approach of an α− particle travelling with a velocity v towards Al(Z=13) nucleus is d. The closest distance of approach of an α−particle travelling with velocity 4v towards Fe(Z=26) nucleus is-

A particle executes SHM with a time period of 8 s. Find the time taken by the particle to go directly from its mean position to half of its amplitude.

16.Sec40+Sec80+Sec160=?

At a certain point in a strained material, the intensities of stresses on two mutually perpendicular planes are 150 N/mm2 (tensile) and 70 N/mm2 (tensile). If the maximum shear stress is 60 N/mm2. The shear stress on these planes will be nearly

nitrogen gas is filled in an insulated container if alpha fraction of moles dissociated without exchane of any energy then the fractional change in is temperature is

A difference of 2.3 eV separates two energy levels in an atom. Whatis the frequency of radiation emitted when the atom make atransition from the upper level to the lower level?

Heat is supplied to a diatomic gas at constant pressure.The ratio of ΔQ:ΔU:ΔW is

Define electricity

TV waves have a wavelength range of 1-10 meter. Their frequency range in MHz is

The value of integral ∫dx(x+2)√x+1 is (where C is integration constant)

In the earth-moon system, if T1 and T2 are period of revolution of earth and moon respectively about the centre of mass of the system then

Two mirrors are inclined at an angle θ. For an object placed in front of them, 11 images are noticed. Find the angle between the mirrors.

From the top of a tower, a particle is thrown vertically downwards with a velocity of 10 m/s. The ratio of distances covered by it in the 3rd and 2nd seconds of its motion is (Take g=10 m/s2)

.A disc revolves in horizontal plane at a steady rate of 3 rev/s. A coin just remains on the disc if kept at a distance of 2 cm from the axis of rotation.What is the coefficient of friction between thecoin and the disc(A) 0-5(C) 0-7(B) 0-65(D) 0-75.

If →a=^i+2^j+4^k, →b=^i+λ^j+4^k, →c=2^i+4^j+(λ2−1)^k, are coplanar vectors and →a,→c are not parallel, then |→a×→c| is equal to

A Proton and electron are placed 1.6 CM apart in free space find the magnitude of electrostatic force between them and the nature of the force

Water in a bucket is whirled in a vertical circle with a string attached to it. The water does not fall down even when the bucket is inverted at the top of its path. We conclude that in this position.

An arc lamp requires a direct current of 10 A at 80 V to function. If it is connected to a 220 V(rms), 50 Hz supply, the series inductor needed for it to work, is close to-

Find the net force acting on pulley 2 assuming all strings and pulleys to be of negligible mass and all surfaces to be frictionless. g=10 m/s2.

Two cars A and B move on a straight road with constant velocity. When they move in same direction, they come close by 8 m in 10 s and when they move in opposite direction towards each other, they come close by 20 m in 1 s. The speed of the cars A and B (in m/s) respectively are

Equation of a progressive wave is given by y=0.2cos π(0.04t+0.02x−π6) where distances are in cm and time in s. What will be the minimum distance between two particles having phase difference of π2?

Three tuning forks of frequencies 500 Hz, 501 Hz and 502 Hz respectively are vibrated simul†an eously. The beat frequency heard will be Options: a-Zero b-1 Hz c-2 Hz d- 3 Hz

A circular plate of radius r is placed on a principal axis at distance from a convex mirror of focal length f' . Such that the Principal axis passes through centre of plate normally. The are of image of the plate is .

Force required to pull a rectangular plate of length 2 cm and breadth 3 cm from water surface for which surface tension is 75 dyne/cm is

A ball of mass m is initially at rest. A variable force starts acting on it in a fixed direction, whose magnitude changes with time. The force - time graph is shown in the figure.Find the speed of the ball at the end of time t=T seconds.