X-rays region lies between Gamma rays and ultraviolet region. 515. (3) A star appears twinkling in the sky because of refraction of light by atmosphere. Light bends when it passes obliquely from one medium to another. This is called refraction of light.

Correct Option: C

X-rays region lies between Gamma rays and ultraviolet region. 515. (3) A star appears twinkling in the sky because of refraction of light by atmosphere. Light bends when it passes obliquely from one medium to another. This is called refraction of light.

Materials for rain proof coats and tents owe their water proof properties to Surface Tension. The surface of a liquid behaves like an elastic membrane and therefore, has a tendency to contract. This property of liquid is called Surface Tension.

Correct Option: A

Materials for rain proof coats and tents owe their water proof properties to Surface Tension. The surface of a liquid behaves like an elastic membrane and therefore, has a tendency to contract. This property of liquid is called Surface Tension.

Solar cells work on the principle of photovoltaic effect.

Correct Option: A

Solar cells work on the principle of photovoltaic effect.

Microwave electromagnetic radiation is used for satellite communication.

Correct Option: C

Microwave electromagnetic radiation is used for satellite communication.

The property of conductor due to which it opposes the flow of current through it is called Resistance. It is numerically equal to the ratio of potential difference across its ends to the current flowing through it. The SI unit of resistance is ohm.

Correct Option: C

The property of conductor due to which it opposes the flow of current through it is called Resistance. It is numerically equal to the ratio of potential difference across its ends to the current flowing through it. The SI unit of resistance is ohm.