Two identical charged spheres are suspended by strings of equal lengths. The strings make an angle of 30° with each other. When suspended in a liquid of density 0.8 g cm-3, the angle remains the same. If the density of the material of the sphere is 1.6 g cm-3, what is the dielectric constant of the liquid?

Anonymous User Physics Electrostatic 12 May, 2020 1 Answer 74 views

A small particle of mass m is projected at an angle  with the x-axis with an initial velocity v0 in the x-y plane as shown in the figure.

At a time  the angular momentum of the particle is

Note: are unit vectors along x, y and z-axis respectively.

Anonymous User Physics Circular and Rotational Motion 12 May, 2020 1 Answer 69 views


Two fixed frictionless inclined planes making an angle 30° and 60° with the vertical are shown in the figure. Two blocks A and B are placed on the two planes. What is the relative vertical acceleration of A with respect to B?

Anonymous User Physics Laws of Motion and Friction 12 May, 2020 1 Answer 61 views










Let C be the capacitance of a capacitor discharging through a resistor R. Suppose t1 is the time taken for the energy stored in the capacitor to reduce to half its initial value and t2 is the time taken for the charge to reduce to one-fourth its initial value. Then what will be the ratio t1/t2

Anonymous User Physics Electromagnetic Induction & Alternating Current 11 May, 2020 1 Answer 61 views

The masses of neutron and proton are 1.0087 amu and 1.0073 amu respectively. If a helium nucleus (alpha particles) of mass 4.0015 amu is formed by combining neutrons and protons. The binding energy of the helium nucleus will be (1 amu = 931 MeV)

Anonymous User Physics Nuclear physics 11 May, 2020 1 Answer 61 views




In a series LCR circuit R = 200  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

Anonymous User Physics Electromagnetic Induction & Alternating Current 11 May, 2020 1 Answer 74 views

Let there be a spherically symmetric charge distribution with charge density varying as upto r = R, and r(r) = 0 for r > R, where r is the distance from the origin. The electric field at a distance r (r < R) from the origin is given by

Anonymous User Physics Electrostatic 11 May, 2020 1 Answer 67 views




20 g of non-electrolyte, non-volatile solute (CxH2xOx), when dissolved in 100 gm water at 100°C, lowers the vapour pressure of solution by 1/100 th of the vapour pressure of pure water at this temperature. What is formula of the compound?

Anonymous User Chemistry Solutions 11 May, 2020 1 Answer 265 views









A nucleus of mass M + ∆m is at rest and decays into two daughter nuclei of equal mass M / 2 each. Speed of light is c.

The binding energy per nucleon for the parent nucleus is E1 and that for the daughter nuclei is E2. Then

Anonymous User Physics Atomic Physics 10 May, 2020 1 Answer 60 views

An initially parallel cylindrical beam travels in a medium of refractive index  where  and  are positive constants and I is the intensity of the light beam. The intensity of the beam is decreasing with increasing radius.

 What will be the initial shape of the wavefront of the beam?

Anonymous User Physics Wave Optics 10 May, 2020 1 Answer 54 views

An initially parallel cylindrical beam travels in a medium of refractive index  where  and  are positive constants and I is the intensity of the light beam. The intensity of the beam is decreasing with increasing radius.

What will be the speed of light in the medium?

Anonymous User Physics Wave Optics 10 May, 2020 1 Answer 69 views

An initially parallel cylindrical beam travels in a medium of refractive index  where  and  are positive constants and I is the intensity of the light beam. The intensity of the beam is decreasing with increasing radius.

As the beam enters the medium, it will

Anonymous User Physics Wave Optics 10 May, 2020 1 Answer 66 views

A transparent solid cylindrical rod has a refractive index of . It is surrounded by air. A light ray is incident at the mid-point of one end of the rod as shown in the figure

The incident angle θ for which the light ray grazes along the wall of the rod is

Anonymous User Physics Ray Optics 09 May, 2020 1 Answer 65 views

A long metallic bar is carrying heat from one of its ends to the other end under steady-state. The variation of temperature θ along the length x of the bar from its hot end is best described by which of the figures?

Anonymous User Physics Heat Transfer 09 May, 2020 1 Answer 55 views


Consider a rubber ball freely falling from a height h = 4.9 m onto a horizontal elastic plate. Assume that the duration of collision is negligible and the collision with the plate is totally elastic. Then what will be the velocity as a function of time and the height as function of time? 

Anonymous User Physics Work Power and Energy 09 May, 2020 1 Answer 70 views

A motor cycle starts from rest and accelerates along a straight path at 2 m/s2. At the starting point of the motor cycle there is a stationary electric siren. How far has the motor cycle gone when the driver hears the frequency of the siren at 94% of its value when the motor cycle was at rest? (Speed of sound = 330 ms-1).

Anonymous User Physics Work Power and Energy 09 May, 2020 1 Answer 68 views






An inductor of inductance L = 400 mH and resistors of resistances R1 = 2  and R2 = 2  are connected to a battery of emf 12 V as shown in the figure. The internal resistance of the battery is negligible. The switch S is closed at t = 0. What will be the potential drop across L as a function of time?

Anonymous User Physics Electromagnetic Induction & Alternating Current 09 May, 2020 1 Answer 78 views

In an experiment the angles are required to be measured using an instrument. 29 divisions of the main scale exactly coincide with the 30 divisions of the vernier scale. If the smallest division of the main scale is half-a-degree (= 0.5°), then the least count of the instrument will be 

Anonymous User Physics 09 May, 2020 1 Answer 60 views

Two wires are made of the same material and have the same volume. However wire 1 has cross-sectional area A and wire 2 has cross-sectional area 3A. If the length of wire 1 increases by ∆x on applying force F, how much force is needed to stretch wire 2 by the same amount?

Anonymous User Physics 09 May, 2020 1 Answer 63 views