In an explosion, an internal impulse acts in order to propel the parts of a system (often a single object) into a variety of directions. After the explosion, the individual parts of the system (that is often a collection of fragments from the original object) have momentum. If the vector sum of all individual parts of the system could be added together to determine the total momentum after the explosion, then it should be the same as the total momentum before the explosion. Just like in collisions, total system momentum is conserved.

Correct Option: A

In an explosion, an internal impulse acts in order to propel the parts of a system (often a single object) into a variety of directions. After the explosion, the individual parts of the system (that is often a collection of fragments from the original object) have momentum. If the vector sum of all individual parts of the system could be added together to determine the total momentum after the explosion, then it should be the same as the total momentum before the explosion. Just like in collisions, total system momentum is conserved.

In a spherical mirror, one of the two curved surfaces is coated with a thin layer of silver followed by a coating of red lead oxide paint. Thus, one side of the spherical mirror is opaque and the other side is a highly polished reflecting surface.

Correct Option: B

In a spherical mirror, one of the two curved surfaces is coated with a thin layer of silver followed by a coating of red lead oxide paint. Thus, one side of the spherical mirror is opaque and the other side is a highly polished reflecting surface.

In telecommunications and signal processing, frequency modulation (FM) conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant. In analogue television, the sound portion of a broadcast is invariably modulated separately from the video. Most commonly, the audio and video are combined at the transmitter before being presented to the antenna, but in some cases separate aural and visual antennas can be used.

Correct Option: B

In telecommunications and signal processing, frequency modulation (FM) conveys information over a carrier wave by varying its instantaneous frequency. This contrasts with amplitude modulation, in which the amplitude of the carrier is varied while its frequency remains constant. In analogue television, the sound portion of a broadcast is invariably modulated separately from the video. Most commonly, the audio and video are combined at the transmitter before being presented to the antenna, but in some cases separate aural and visual antennas can be used.

The speed of sound in air depends on the density of air and the density of air depends on the temperature. The speed of sound is unaffected by pressure. If the atmospheric pressure changes, the speed of sound in air remains constant.

Correct Option: A

The speed of sound in air depends on the density of air and the density of air depends on the temperature. The speed of sound is unaffected by pressure. If the atmospheric pressure changes, the speed of sound in air remains constant.

The stars’ light must travel through the Earth’s multi-layered atmosphere, and as it does so it is refracted (bent) multiple times and in random directions. The phenomenon of random refraction appears to make the star wink as though it is in motion. It is this action that our eyes translate as twinkling. When the light itself enters the air – or atmosphere – it is scattered, with the scattering depending on the air temperature with warm air causing less bends and colder air causing more.

Correct Option: B

The stars’ light must travel through the Earth’s multi-layered atmosphere, and as it does so it is refracted (bent) multiple times and in random directions. The phenomenon of random refraction appears to make the star wink as though it is in motion. It is this action that our eyes translate as twinkling. When the light itself enters the air – or atmosphere – it is scattered, with the scattering depending on the air temperature with warm air causing less bends and colder air causing more.