An electric motor operates at 20 r.p.s. What will be the approximate power delivered by the motor, if it supplies a torque of 75 N-m?
Which of th following transitions in a hydrogen atom emits the photon of highest frequency?
1 Crore+ students have signed up on EduRev. Have you? Download the App |
The ratio of the longest to shortest wavelengths in Brackett series of hydrogen spectra is
Potential difference across the terminals of a battery is 50 V, when 11 A current is drawn. And it is 60 V, when 1 A current is drawn. The e.m.f. and internal resistance of battery is
When an inert gas is filled in the place vacuum in a photo cell, then
Light of frequency 4v₀ is incident on the metal of the threshold frequency v₀. The maximum kinetic energy of the emitted photoelectrons is
An L.C. circuit contains 10 mH inductor and a 25 μ F capacitor. The resistance of the circuit is negligible. The energy stored in the circuit is completely magnetic at time (in milli seconds) being measured from the instant when the circuit is closed
Minimum no. of 8 μF and 250 V capacitors, used to make a combination of 16 μF and 1000 V, is
The ratio of charge to potential of a capacitor is known as its
To aviod slipping while walking on ice, one should take smaller steps because of the
The acceleration due to gravity on the planet A is 9 times the acceleration due to gravity on planet B. A man jumps to a height of 2 m on the surface of A. What will be the height of jump by the same person on the planet B?
When a body is heated, which colour corresponds to highest temperature
A vessel contains a mixture of one mole of oxygen and two moles of nitrogen at 300 K. The ratio of the average rotational kinetic energy per O₂ molecule to that per N₂ molecule is
When a charged particle moves perpendicular to a magnetic field, then
The force between two short bar magnets with magnetic moments M₁ and M₂ whose centres are r meter apart is 8 N, when their axes are in same line. If the separation is increased to 2 r, the force between them is reduced to
Oil spreads over the surface of water, whereas water does not spread over the surface of oil, because
A 20 cm long capillary tube is dipped in water. The water rises up to 8 cm. If entire arrangement is put in a freely elevator, the length of water column in the capillary tube will be
A particle covers 150 m in 8th second when starts from rest, its acceleration is
The resultant of two forces, one double the other in magnitude, is perpendicular to the smaller of the two forces. The angle between the two forces is
Two vectors A̅ and B̅ are such that A̅ + B̅ = A̅ - B̅. Then
A car of mass 12kg at rest explodes into two pieces of masses 4kg and 8kg which move in opposite direction. If the velocity of 8kg piece is 6 m/s, the kinetic energy of other piece is
The image formed by an objective lens of a compound microscope is
A chimpanzee, swinging on a swing in a sitting position, stands up suddenly. The time period will
An instantaneous displacement of a simple harmonic oscillator is x = A cos (ωt + π/4 ). Its speed will be maximum at time
A ray of light is incident on a plane mirror at an angle of 60o . The angle of deviation produced by the mirror is
Two spheres of masses 2M and M are initially at rest at a distance R apart. Due to mutual force of attraction, they approach each other. When they are at separation R/2, the acceleration of the centre of mass of spheres would be
A soild sphere, disc and solid cylinder all of the same mass and made of the same material are allowed to roll down (from rest) on an inclined plane, then
A small steel sphere is tied to a string and is whirled in a horizontal circle with a uniform angular velocity ω₁. The string is suddenly pulled so that radius of the circle is halved. If ω₂ is new angular velocity. then