4.both force and acceleration
3rd law of motion explains
1.effect of force
2.existence of a force
3.existence of two forces
4.existence of pair of forces in nature
A body is falling freely under gravity. How much distance it falls during an interval of time between 1st and 2nd seconds of its motion, taking g=10?
3.direction of motion changes
4.displacement from origin changes
Area under velocity time graph represent
1.provide him a larger inertia
2.decreases his inertia
3.decreases his momentum
4.increases his momentum
1.It does emit ?-radiation.
2.Its size as compare to proton and neutron is very small.
3.No antiparticle of electron is present.
4.The velocity of electron must be very high according to uncertainty principle.
In an X-ray tube electrons each of charge e are accelerated through V potential difference allowed to hit a metal target. The wavelength of the X-rays emitted is
4.impossible to predict
3.Electrons of He.
In laser production the state in which more atoms are in the upper state than in the lower one is called
1.Metal stable state.
4.All the above.
3.Cause X-ray emission.
4.Cause laser production
1.has zero acceleration
2.has uniform acceleration
3.has variable acceleration
4.moves in a circle
1.Number of incident electron i.e. filament current.
2.The kinetic energy of the incident electron i.e. the potential difference through which they are accelerated.
3.The soft target which can easily emit electrons.
4.all of above are correct.
Momentum depends upon
1.force acts on the body
2.mass of the body
3.velocity of the body
4.both mass and velocity of the body
1.chance of collision
3.move with high velocity
4.move with velocity comparable to velocity of light
Quality of X-rays depends upon ___________ A-filament current B-accelerating voltage C-material of the target
4.A B & C
Reflecting mirrors in laser is used to
3.For producing more energetic lasers.
Slope of velocity time graph is
Taking off rocket can be explained by
1.1st law of motion
2.2nd law of motion
3.Law of conservation of momentum
4.law of conservation of energy
The acceleration in the rocket at any instant is proportional to the nth power of the velocity of the expelled gases. Where the value of n must be?
1.The illumination of the target metal by ultra-violet radiation.
2.The bombardment of the target by protons.
3.The bombardment of target by electrons.
4.The absorption of ? radiation by the target metal.
1.solid and soft
2.soft and elastic
3.solid and hard
4.hard and elastic
The dimension of force is
1.Reducing the pressure or cooling the target.
2.Increasing the temperature of the filament.
3.Using a target element of higher atomic number.
4.Increasing the potential difference between the cathode and the target.
The minimum wavelength of X-rays produced by the bombardment of electrons on the screen of a television set where the accelerating potential is 2.0K V will be
1.6.2 x 10-10m
2.9.1 x 10-18m
3.3.11 x 10-10m
4.4 x 10-10m
1.? - rays
2.? - rays
3.? - rays
4.all of above
3.constant if the rate of ejected gases is constant
4.constant for short range rocket.
The velocity of laser light is
1.Less than ordinary light.
2.More than ordinary light.
3.Equal to ordinary light.
4.Different for different colours or frequency.
UV radiation can be produced by
1.Heating the filament.
2.Electron excitation in the gas.
3.Ionization of atoms.
4.All the above.
1.Line spectrum of atoms.
2.Production of x-rays.
3.Diffraction by crystalline solids.
1.straight inclined line.
3.acceleration is zero
4.both (a) and (b)
3.its position vector
When car takes turn around a curve road, the passengers feel a force acting on them in a direction away from the center of the curve. It is due to
1.momentum changes but K.E remain conserve
2.K.E changes but momentum remain conserve
3.both momentum and K.E changes
4.both momentum and K.E conserve
When two bodies move toward each other with constant speeds the distance between them decreases at the rate of 6m / sec. If they move in the same direction the distance between them increases at the rate of 4m/sec. Then their speeds are
1.acceleration is const
2.acceleration is variable
3.acceleration is zero
4.velocity is zero
4.all 1st, 2nd and 3rd laws
1.a gas filled ballon
2.bullet fired from gun
3.a football kicked
4.a base ball shot
1.The ions in a crystal are well arranged.
2.The lines in a diffraction grating cannot reflect X-rays.
3.The penetration power of X-rays is high in a diffraction grating.
4.The wavelengths of X-rays are of the same order of magnitude as the separation between atoms in a crystal