1st law of motion gives the definition of
1.rest
2.motion
3.velocity
4.force
2nd law of motion gives the definition of
1.force
2.acceleration
3.velocity
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?
1.14 m
2.20 m
3.5 m
4.25 m
A body is moving with uniform velocity. Its
1.speed changes
2.acceleration changes
3.direction of motion changes
4.displacement from origin changes
A man is in a car is moving with velocity of 36km/hr. His speed with repect to the car is
1.10m/s
2.36m/s
3.zero
4.infinite
Area under velocity time graph represent
1.force
2.displacement
3.distance
4.acceleration
During long jump, athlete runs before taking the jump. By doing so he
1.provide him a larger inertia
2.decreases his inertia
3.decreases his momentum
4.increases his momentum
Electron cannot exist in the nucleus it is confirmed by observing that
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
1.he/ev
2.he/Vc
3.eV/h
4.impossible to predict
In He-Ne laser the lasing action is produced by
1.Ne only.
2.He-Ne both
3.Electrons of He.
4.Electrons Ne.
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.
2.Normal state.
3.Inverted population.
4.All the above.
In normal state of energy the incident high energy photons will be
1.Stimulated.
2.Absorbed.
3.Cause X-ray emission.
4.Cause laser production
Inertia of an object is quantitative measure of its
1.volume
2.density
3.mass
4.temperature
Instantaneous and average velocities become equal when body
1.has zero acceleration
2.has uniform acceleration
3.has variable acceleration
4.moves in a circle
Maximum frequency in the spectrum from X-ray tube is directly proportional to the
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
Motorcycle safety helmet extends the time of collision hence decreasing the
1.chance of collision
2.force acting
3.velocity
4.impulse
Newtons laws do not hold good for particles
1.at rest
2.moving slowly
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
1.A&B
2.B&C
3.A&C
4.A B & C
Radiation produced from TV picture tube is
1.?-rays
2.X-rays
3.Far infrared.
4.Infrared
Reflecting mirrors in laser is used to
1.Further stimulation
2.Lasing more
3.For producing more energetic lasers.
4.All
Slope of velocity time graph is
1.acceleration
2.distance
3.force
4.momentum
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.-1
2.1
3.2
4.-2
The characteristic X-rays spectrum is due to
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.
The collision between two bodies be elastic if bodies are
1.solid and soft
2.soft and elastic
3.solid and hard
4.hard and elastic
The dimension of force is
1.MLT-2
2.ML2T-2
3.ML2T2
4.ML-2T-2
The metastable state for an atom in laser light is
1.10-4 sec
2.10-5 sec
3.10-3 sec
4.10-8 sec
The minimum wavelength of X-rays can further be reduced by
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
The penetrating power of X-rays is comparable with that of
1.? - rays
2.? - rays
3.? - rays
4.all of above
The thrust on the rocket in the absence of gravitational force of attraction is
1.constant
2.not constant
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.
Wave-like characteristic of electron is demonstrated by
1.Line spectrum of atoms.
2.Production of x-rays.
3.Diffraction by crystalline solids.
4.Photoelectric effect.
What is the angle of projection for which the range and maximum height become equal?
1.tan-1 1/4
2.tan-1 4
3.tan-1 1/2
4.tan-1 2
What is the shape of velocity, time graph for constant acceleration?
1.straight inclined line.
2.parabola
3.inclined curve
4.declined curve
What is the velocity of a particle of mass m & de-Broglie wavelength ??
1.h/m?
2.2h/m?
3.mh/h
4.(2hc/m?)1/2
When a body moves in a straight line then its displacement coincides with
1.distance
2.force
3.acceleration is zero
4.both (a) and (b)
When body is in motion, ________ always changes.
1.its velocity
2.its acceleration
3.its position vector
4.its momentum
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.centripetal force
2.gravitational force
3.their inertia
4.centrifugal force
When collision between the bodies in a system is inelastic in nature then for system
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
1.5m/s, 1m/s
2.3m/s, 3m/s
3.6m/s, 1m/s
4.4m/s, 2m/s
When velocity time graph is a straight line parallel to time axis then
1.acceleration is const
2.acceleration is variable
3.acceleration is zero
4.velocity is zero
Which law of motion is also called law of inertia?
1.1st law
2.2nd law
3.3rd law
4.all 1st, 2nd and 3rd laws
Which of the following is not an example of projectile motion.
1.a gas filled ballon
2.bullet fired from gun
3.a football kicked
4.a base ball shot
Which of the following pair has same direction always?
1.force, displacement
2.force, velocity
3.force, acceleration
4.force, momentum
Which shows the correct relation between time of flight T and maximum height H?
1.H=gT2/8
2.H=8T2/g
3.H=8g/T2
4.H=gT2
X-rays are diffracted by a crystal but not by a diffraction grating because
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