The effective value of alternating current passing through 24 Ω resistor is 5 A. The maximum potential difference across the resistor is
K1 and K2vare the maximum kinetic energies of the photoelectrons emitted when light of wavelengths λ1 and λ2 respectively are incident on a metallic surface. If λ1 = 3 λ2 , then
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The resonant frequency of a circuit is f. If the capacitance is made 4 times the initial value, then the resonant frequency will becomes
A ball of mass 0.25 kg attached to the end of a string of length 1.96 m is moving in a horizontal circle. The string will break if the tension is more than 25 N. What is the maximum speed with which the ball can be moved
A capacitor of capacity C₁ is charged by connecting it across a battery of e.m.f. V₀. The battery is then removed and the capacitor is connected in parallel with an uncharged capacitor of capacity C₂. The potential difference across this combination is
The power dissipated across resistance R which is connected across a battery of potential V is P. If resistance is doubled, then the power becomes
An electric motor operates on a.d.c. source of e.m.f. V and internal resistance R. The power output of the source is maximum when the current drawn by the motor is
A long solenoid has 500 turns . When a current of 2 ampere is passed through it , the resulting magnetic flux linked with each turn of the solenoid is 4 x 10-3 Wb. The self-inductance of the solenoid is
Which of the following radiations has the least wavelength?
The ratio of charge to potential of a capacitor is known as its
Two electric charge 12 μC and −6 μC are places 20 cm apart in air. There will be a point P at which electric potential is zero on the line joining these two charges and outside, excluding the region between them. The distance of P from −6 μC charge is
A fireman of mass 60 kg slides down a pole. He is pressing the pole with a force of 600 N. The coefficient of friction between the hands and the pole is 0.5, with what acceleration will the fireman slide down (g=10m/s2)
Choose the correct statement from the following. The radius of the orbit of a geostationary satellite depends upon
A black body is heated from 27oC to 127oC. The ratio of their energies of radiations emitted will be
In Young's doulbe-slit experiment, instead of light, a beam of electron is used. The slit width is d. When the velocity of electron is increased, then
The volume of a gas will be double of what it is at 0oC (pressure remaining constant) at
Two circular coils of equal radii 2√2 x 10-2 m and having number of turns 2 each are arranged in perpendicular plane such that their centres coincide. Find the (i) Magnetic field at the centre due to each coil (ii) Resultant magnetic field at centre. They are carrying currents of 20mA each
The monoenergetic beams of electrons moving along +y direction enters a region of uniform electric and magnetic fields. If the beam goes straight through, then these simultaneously fields B̅ and E̅ are directed respectively
The magnetic field of given length of wire for single turn coil at its centre is B, then its value for two turns coil for the same wire is
Using a bar magnet P, a vibration magnetometer has time period 2 seconds. When a bar Q (identical to P in mass and size) is placed on top of P, the time period is unchanged. Which of the following statements is true ?
If a diamagnetic substance is brought near the north or the south pole of a bar magnet, it is:
The shape of a liquid drop becomes spherical due to its
A beaker containing a liquid of density (ρ) moves up with an acceleration (a). The pressure due to liquid at a depth (h) below the surface of the liquid is
A wire of length L and cross-section A is made of material of Young's modulus Y. If it is stretched by an amount x, then work done is
A cylinder of 500 g and radius 10 cm has moment of inertia (about its natural axis)
The position of a particle moving in the xy-plane at any time t is given by x = (3t2-6t) metres, y = (t2-2t) metres. Select the correct statement about the moving particle from the following
A man fires a bullet of mass 200 g at a speed of 5 m/s. The gun is of one kg mass. by what velocity the gun rebounds backwards