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 58 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 59 views

## A particle is moving with velocity  where K is a constant. The general equation for its path is A particle is moving with velocity where K is a constant. The general equation for its path is

Anonymous User Physics Laws of Motion and Friction 11 May, 2020 58 views

In the circuit shown below, the key K is closed at t = 0. What will be the current through the battery? Anonymous User Physics Electromagnetic Induction & Alternating Current 11 May, 2020 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 70 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 63 views

Degree of dissociation of three binary electrolytes AB, CD and EF are 60%, 20% and 100% in the solution having same mole fraction of water. Ratio of lowering in vapour pressure of their solution is

Anonymous User Chemistry Solutions 11 May, 2020 105 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 243 views

A complex is written as M(en)y.xBr. Its 0.05 molar solution shows 2.46 atm osmotic pressure at 27°C.Assuming 100% ionisation and coordination number of metal (III) is six, complex may be

Anonymous User Chemistry Solutions 11 May, 2020 133 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 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 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 68 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 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 64 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 55 views

A charge Q is placed at each of the opposite corners of a square. A charge q is placed at each of the other two corners. If the net electrical force on Q is zero, then what will be the Q/q ?

Anonymous User Physics Electrostatic 09 May, 2020 65 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 69 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 64 views

## A particle has an initial velocity and an acceleration of . What will be its speed after 10 s? A particle has an initial velocity and an acceleration of . What will be its speed after 10 s?

Anonymous User Physics Kinematics 09 May, 2020 58 views

The surface of a metal is illuminated with the light of 400 nm. The kinetic energy of the ejected photoelectrons was found to be 1.68 eV. The work function of the metal is (hc = 1240 eV nm)

Anonymous User Physics Electrostatic 09 May, 2020 61 views

Two moles of helium gas are taken over the cycle ABCDA, as shown in the P - T diagram The net work done on the gas in the cycle ABCDA is

Anonymous User Physics Thermodynamics 09 May, 2020 65 views

Two moles of helium gas are taken over the cycle ABCDA, as shown in the P - T diagram The work done on the gas in taking it from D to A is

Anonymous User Physics Thermodynamics 09 May, 2020 73 views

Two moles of helium gas are taken over the cycle ABCDA, as shown in the P - T diagram Assuming the gas to be ideal the work done on the gas in taking it from A to B is

Anonymous User Physics Thermodynamics 09 May, 2020 55 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 74 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 57 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 62 views

The height at which the acceleration due to gravity becomes g/9 (where g = the acceleration due to gravity on the surface of the earth) in terms of R, the radius of the earth is

Anonymous User Physics Gravitation and Projectile 09 May, 2020 54 views

Image of an object approaching a convex mirror of radius of curvature 20 m along its optical axis is observed to move from 25/3 m to 50/7 m in 30 seconds. What is the speed of the object in km per hour?

Anonymous User Physics Ray Optics 08 May, 2020 72 views

The focal length of a thin biconvex lens is 20 cm. When an object is moved from a distance of 25 cm in front of it to 50 cm, the magnification of its image changes from m25 to m50. The ratio m25/m50 is

Anonymous User Physics Ray Optics 08 May, 2020 62 views

Two identical glass rods S1 and S2 (refractive index = 1.5) have one convex end of radius of curvature 10 cm. They are placed with the curved surfaces at a distance d as shown in the figure, with their axes (shown by the dashed line) aligned. When a point source of light P is placed inside rod S1 on its axis at a distance of 50 cm from the curved face, the light rays emanating from it are found to be parallel to the axis inside S2.The distance d is Anonymous User Physics Ray Optics 08 May, 2020 68 views

A point source S is placed at the bottom of a transparent block of height 10 mm and refractive index 2.72. It is immersed in a lower refractive index liquid as shown in the figure. It is found that the light emerging from the block to the liquid forms a circular bright spot of diameter 11.54 mm on the top of the block. The refractive index of the liquid is? Anonymous User Physics Ray Optics 08 May, 2020 86 views

A ray of light travelling in the direction is incident on a plane mirror. After reflection, it travels along the direction . The angle of incidence is

Anonymous User Physics Ray Optics 08 May, 2020 55 views

A bi-convex lens is formed with two thin plano convex lenses. Refractive index n of the first lens is 1.5 and that of the second lens is 1.2. Both the curved surfaces are of the same radius of curvature R = 14 cm. For this bi-convex lens, for an object distance of 40 cm, the image distance will be.

Anonymous User Physics Ray Optics 08 May, 2020 61 views

The image of an object, formed by a plano-convex lens at a distance of 8 m behind the lens, is real is one-third the size of the object. The wavelength of light inside the lens is 3 times the wavelength in free space.The radius of the curved surface of the lens is

Anonymous User Physics Ray Optics 08 May, 2020 65 views

A biconvex lens of focal length 15 cm is in front of a plane mirror. The distance between the lens and the mirror is 10 cm. A small object is kept at a distance of 30 cm from the lens. The final image is

Anonymous User Physics Ray Optics 08 May, 2020 112 views

A ball is dropped from a height of 20 m above the surface of water in a lake. The refractive index of water is 4/3. A fish inside the lake, in the line of fall of the ball, is looking at the ball. At an instant, when the ball is 12.8 m above the water surface, the fish sees the speed of ball as [Take g = 10 m/s2.]

Anonymous User Physics Ray Optics 08 May, 2020 61 views

A ray of light traveling in water is incident on its surface open to air. The angle of incidence is , which is less than the critical angle. Then there will be

Anonymous User Physics Ray Optics 08 May, 2020 60 views

In an experiment to determine the focal length (f) of a concave mirror by the u-v method, a student places the object pin A on the principal axis at a distance x from the pole P. The student looks at the pin and its inverted image from a distance keeping his/her eye in line with PA. When the student shifts his/her eye towards left, the image appears to the right of the object pin. Then

Anonymous User Physics Ray Optics 08 May, 2020 65 views

A thin lens has a focal length f and its aperture has a diameter d. It forms an image of intensity I. Now, the outer part extending from R/2 to R is blackened. The focal length of the lens and intensity of image becomes/remain (R = radius of aperture = d/2 )

Anonymous User Physics Ray Optics 08 May, 2020 64 views