20. In a Young's double slit experiment, slits are separated by 0.5 mm, and the screen is placed 150 cm away. A beam of light consisting of two wavelengths, 650 nm and 520 nm, is used to obtain interference fringes on the screen. The least distance from the common central maximum to the point where the bright fringes due to both the wavelengths coincide is :
Stars appears to move from east to west because
Magnetism at the centre of a bar magnet is
An astronaut or other body in the spacecraft is said to be weightlessness or?
A car is moving on a circular path and takes a turn. If R1 and R2 be the reaction on the inner and outer wheels respectively, then
Superposition theorem is not applicable for
Consider the following statements and select the correct code.
Assertion (A): The velocity of sound in air increased due to the presence of moisture in it. Reason (R): The presence of moisture in air lowers the density of air.
If two bodies of different masses, initially at rest, are acted upon by the same force for the same time, then the both bodies acquire the same
A prism having refractive index 1.414 and refracting angle 30° has one of the refracting surfaces silvered. A beam of light incident on the other refracting surface will retrace its path, if the angle of incidence is ______.
The mass of the body will?
If the value of gravitational acceleration at a height h above the Earth’s surface is the same as that at a depth d below the Earth’s surface (with both h and d small compared to the Earth’s radius R), then
If we drop a ball in horizontal direction than its motion will no longer be straight downward but will be at some?
A In Young's double slit experiment if monochromatic light used is replaced by white light, then _______.
A certain current on passing through a galvanometer produces a deflection of 100 divisions. When a shunt of one ohm is connected, the deflection reduces to 1 division. The galvanometer resistance is
Rectifiers are used to convert
One Kilowatt-hour is equal to?
The Universal law of gravitation must apply to?
If the linear momentum of a body is increased by 50%, then the kinetic energy of that body increases by _____
Suitable impurities are added to a semiconductor depending on its use. This is done in order to
Alexander Graham Bell invented
Consider the following statements:
A body weighs less at the equator than at the poles because:
1. earth rotates about its axis.
2. the ice cap at the poles increases gravitational pull.
3. equatorial diameter is greater than the polar diameter.
4. of some unknown facts.
Which of the statements given above is/are incorrect?
The resistivity of a wire depends on its
The number of dry cells, each of emf 1.5 volt and internal resistance 0.5 ohm that must be joined in series with a resistance of 20 ohm so as to send a current of 0.6 ampere through the circuit is
Rainbow is formed due to a combination of
Identify the set in which all the three materials are good conductor of electricity
Only for non-metallic resistance.
Refractive index of an optical medium chan geswith
1. the nature of the medium.
2. the change in the angle of incidence of the ray.
3. colour of the incident ray.
Select the correct answer using the code given below: