Why is it easier to roll a barrel full of coal tar than to pull it?
Because coal tar is a liquid and it flows in the barrel when it is rolled
Because the rolling friction is much less than the sliding friction
Because more surface area of the barrel is in contact with the road when it is pulled
Because the full weight of the barrel comes into play when it is pulled
Which of the following industry uses mica as a raw material?
Light year is a unit to measure
In which of the following pair, the physical quantities do not have identical dimension?
Force and rate of change of linear momentum
Impulse and moment of force
Pressure and Young''s modules
Planck''s constant and Angular momentum
Sound of frequency below 20 Hz is called
In what order does the velocity of sound increase in these media?`
Iron, water and air
Air, water and iron
Water, iron and air
Iron, air and water
Superconductors are substances which
offer high resistance to the flow of current
conduct electricity at low temperature
conduct electricity at high temperatures
offer no resistance to the flow of electricity
when a room temparature is 15 degrees, the metallic cap of pen is much colder than its plastic body because
plastics have a higher thermal conductivity
metals are good conducter of heat
plastics have a lower density
metals have a higher thermal capacity
Intensity of sound at a point is ____ its distance from the source.
inversely proportional to
directly proportional to square of
inversely proportional to square of
directly proportional to
Which one of the following pairs does not have an idectical dimension?
Impulse and Momentum
Angular momentum and Planck''s constant
Work and Torque
Moment of inertia and moment of a force