Refraction is the change in direction of wave propagation due to a change in its transmission medium.Due to the change of medium, the phase velocity of the wave is changed but its frequency remains constant. Refraction of light is the most commonly observed refractive phenomenon, but any type of wave can refract when it interacts with a medium.

Correct Option: C

Refraction is the change in direction of wave propagation due to a change in its transmission medium.Due to the change of medium, the phase velocity of the wave is changed but its frequency remains constant. Refraction of light is the most commonly observed refractive phenomenon, but any type of wave can refract when it interacts with a medium.

Parsec is a unit of distance used in astronomy to measure large distances to objects outside our Solar System. It is equal to about 3.26 light years (3.086 × 1013 kilometres). One parsec is the distance at which one astronomical unit subtends an angle of one arcsecond.

Correct Option: B

Parsec is a unit of distance used in astronomy to measure large distances to objects outside our Solar System. It is equal to about 3.26 light years (3.086 × 1013 kilometres). One parsec is the distance at which one astronomical unit subtends an angle of one arcsecond.

A beta ray is a high-energy, high-speed electron (negatively charged) or positron (positively charged) emitted in the radioactive decay of an atomic nucleus, such as a potassium-40 nucleus, in the process of beta decay. Two forms of beta decay, b– and b+, respectively produce electrons and positrons. Beta radiation takes the form of either an electron or a positron being emitted from the nucleus of an atom.

Correct Option: B

A beta ray is a high-energy, high-speed electron (negatively charged) or positron (positively charged) emitted in the radioactive decay of an atomic nucleus, such as a potassium-40 nucleus, in the process of beta decay. Two forms of beta decay, b– and b+, respectively produce electrons and positrons. Beta radiation takes the form of either an electron or a positron being emitted from the nucleus of an atom.

A lightning conductor is made up of a sharp pointed metal (usually copper metal, as it is a very good conductor) connected directly to the ground. It is placed higher than the roof so that if lightning strikes, it strikes the conductor before it can reach the house. It should be pointed because when the negative charge is discharged by the cloud, it will first strike the pointed tip of the lightning conductor and quickly travel to the earth. The discharge will be quickly over and the house and its surroundings will be saved from damage. The pointed nature of the lightning conductor helps it to acquire more number of positive charges on its tip.

Correct Option: D

A lightning conductor is made up of a sharp pointed metal (usually copper metal, as it is a very good conductor) connected directly to the ground. It is placed higher than the roof so that if lightning strikes, it strikes the conductor before it can reach the house. It should be pointed because when the negative charge is discharged by the cloud, it will first strike the pointed tip of the lightning conductor and quickly travel to the earth. The discharge will be quickly over and the house and its surroundings will be saved from damage. The pointed nature of the lightning conductor helps it to acquire more number of positive charges on its tip.

The SI unit of magnetic flux is the Weber (Wb) (in derived units: volt-seconds). It is the magnetic flux that, linking a circuit of one turn, would produce in it an electromotive force of 1 volt if it were reduced to zero at a uniform rate in 1 second. It is named after the German physicist Wilhelm Eduard Weber. The CGS unit of magnetic flux is Maxwell.

Correct Option: A

The SI unit of magnetic flux is the Weber (Wb) (in derived units: volt-seconds). It is the magnetic flux that, linking a circuit of one turn, would produce in it an electromotive force of 1 volt if it were reduced to zero at a uniform rate in 1 second. It is named after the German physicist Wilhelm Eduard Weber. The CGS unit of magnetic flux is Maxwell.