A solenoid has an inductance of 60 henrys and a resistance of 30 ohms. If it is connected to a 100 volt battery, how long will it take for the current to reach e-1/e=63.2% of its final value
The force acting between proton and proton inside the nucleus is
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The north pole of a long horizontal bar magnet is being brought closer to a vertical conducting plane, along the perpendicular direction. The induced current in the conducting plane is
The electrical resistance of a mercury column in a cylindrical container is R. When the same mercury is poured into another cylindrical container twice the radius of cross-section, the resistance of mercury column now is
Consider the two following statements A and B and identify the correct choice given in the answers; (A) In photovoltaic cells the photoelectric current produced is not proportional to the, intensity of incident light. (B) in gas filled photoemissive cells, the velocity of photoelectrons depends on the wavelength of the incident radiation.
A body of 2 gm carrying a charge of 0·1 μ C starts from rest at the positive plate and moves to the negative plate of a parallel plate condenser connected to a voltage supply of 30KV. The final velocity is
A block rests on a rough inclined plane making an angle of 30∘ with the horizontal. The coefficient of static friction between block and the plane is 0.8. If the frictional force on the block is 10 N, the mass of block is (g=10m/s2)
In potentiometer experiment a cell of e.m.f. 1.5V connected in the secondary circuit gives a balancing length of 165cm of the wire. If a resistance of 5 Ω is connected parallel to the cell the balancing length of the wire is 150cm. The internal resistance of the cell is
If one mole of monoatomic gas (γ = 5/3) is mixed with one mole of diatomic gas (γ = 7/5), the value of γ for the mixture is
Two concentric uniformly charged spheres of radius 5cm and 10cm are arranged as shown in the figure. Potential difference between the spheres is:
Choose the correct statement from the following : Weightlessness of an astronaut moving in a satellite is a situation of
Two tangent galvanometers having coils of the same radius are connected in series. A current flowing in them produces deflections of 60o and 45orespectively. The ratio of the number of turns in the coils is
The range of voltmeter of resistance 300Ω is 5V. The resistance to be connected to convert it is an ammeter of range 5A is
A capillary tube when immersed vertically in a liquid records a rise of 3 mm. If the tube is immersed in the liquid at an angle of 60o with the vertical, then height of the liquid in the capillary tube will be
In a liquid flowing through a pipe, the pressure difference between its ends is made half and radius is doubled. If the initial rate of flow of liquid was Q, then new rate of flow of liquid through the pipe is
Particle nature and wave nature of electromagnetic waves and electrons be shown by
A body falling from a high Minaret travels 40 metres in the last 2 seconds of its fall to ground. Height of Minaret in metres is (take g=10m/s2)
A mass of 100 gm is tied to one end of string 2 m long. The body is revolving in a horizontal circle making a maximum of 200 revolutions per min. The other end of the string is fixed at the centre of the circle of revolution. The maximum tension that the string can bear is (approximately)
A circular road of radius 1000 m has banking angle 45o. The maximum safe speed of a car having mass 2000 kg will be, if the coefficient of friction between tyre and road is 0.5
The velocity of a body of rest mass m₀ is √3/2c (where c is the velocity of light in vacuum). Then mass of this body is
In an astronomical telescope, the focal lengths of objective lens and eye-piece are 180 cm and 6 cm respectively. In normal adjustment, magnifying power of the astronomical telescope will be
A body executes SHM. The P.E., the K.E. and total energy (T.E.) are measured as a function of displacement x. Which of the following statement is true.
The rotational kinetic energy of a body is E and its moment of inertia is I. The angular momentum is
A spherical shell has mass M and radius R. Moment of inertia about its diameter will be
An electric kettle has two heating coils. When one of the coils is connected to an ac source the water in the kettle boils in 10 minutes. When the other coil is used the water boils in 40 minutes. If both the coils are connected in parallel, the time taken by the same quantity of water to boil will be