In circular motion, the magnitude of the velocity of the body is constant but the direction is constantly changing. This means that, even though the speed is not changing, the velocity is changing. This means that body moving in a circular is accelerating. At any instant, the direction of the velocity is a tangent to the circular path. A body moving at constant speed in a circular path experiences an acceleration directed towards the centre of the circular path. This acceleration is called a centripetal acceleration and is provided by a centripetal force. Overall, the displacement, velocity and acceleration are vector quantities. They change; but kinetic energy remains constant because the speed is constant.

Correct Option: C

In circular motion, the magnitude of the velocity of the body is constant but the direction is constantly changing. This means that, even though the speed is not changing, the velocity is changing. This means that body moving in a circular is accelerating. At any instant, the direction of the velocity is a tangent to the circular path. A body moving at constant speed in a circular path experiences an acceleration directed towards the centre of the circular path. This acceleration is called a centripetal acceleration and is provided by a centripetal force. Overall, the displacement, velocity and acceleration are vector quantities. They change; but kinetic energy remains constant because the speed is constant.

An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. The magnetic field disappears when the current is turned off. It is made of soft iron since it has the property of losing its magnetism very quickly. The soft iron core of the electromagnet makes the magnetic field stronger.

Correct Option: B

An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. The magnetic field disappears when the current is turned off. It is made of soft iron since it has the property of losing its magnetism very quickly. The soft iron core of the electromagnet makes the magnetic field stronger.

Absolute zero is the temperature at which all motion in matter stops and is thought to be unreachable. It is the point at which the fundamental particles of nature have minimal vibrational motion, retaining only quantum mechanical, zero-point energyinduced particle motion. By international agreement, absolute zero is defined as precisely; 0 K on the Kelvin scale, which is a thermodynamic (absolute) temperature scale; and –273.15 degrees Celsius on the Celsius scale.

Correct Option: A

Absolute zero is the temperature at which all motion in matter stops and is thought to be unreachable. It is the point at which the fundamental particles of nature have minimal vibrational motion, retaining only quantum mechanical, zero-point energyinduced particle motion. By international agreement, absolute zero is defined as precisely; 0 K on the Kelvin scale, which is a thermodynamic (absolute) temperature scale; and –273.15 degrees Celsius on the Celsius scale.

Only transverse waves (such as radio, ultraviolet and infrared waves) can be polarized since their vibrations can potentially occur in all directions perpendicular to the direction of travel. It is therefore possible to confine the vibrations to a single plane. However, sound waves are longitudinal in which vibrations are parallel to the direction of travel of the wave. The vibrations of a longitudinal wave occur along a single line, it is therefore not possible to confine that to a plane. So it cannot be polarized.

Correct Option: D

Only transverse waves (such as radio, ultraviolet and infrared waves) can be polarized since their vibrations can potentially occur in all directions perpendicular to the direction of travel. It is therefore possible to confine the vibrations to a single plane. However, sound waves are longitudinal in which vibrations are parallel to the direction of travel of the wave. The vibrations of a longitudinal wave occur along a single line, it is therefore not possible to confine that to a plane. So it cannot be polarized.

The motion of a projectile is a two-dimensional motion—Horizontal motion and vertical motion—that take place independent of each other. The horizontal velocity of a projectile is constant (a never changing in value). The force of gravity continuously affects the vertical component, so the vertical motion is a uniformly accelerated motion.

Correct Option: C

The motion of a projectile is a two-dimensional motion—Horizontal motion and vertical motion—that take place independent of each other. The horizontal velocity of a projectile is constant (a never changing in value). The force of gravity continuously affects the vertical component, so the vertical motion is a uniformly accelerated motion.