Physics

Gamma rays are electromagnetic radiation and have no charge, so they are not deflected by electric or magnetic fields, unlike alpha and beta rays which are charged particles and do get deflected.

A Newton metre (N·m) is the SI unit of torque, which measures the rotational force applied at a distance from a pivot point. It is not used for substance, length, or work (work is measured in joules).

A parsec is a unit of distance used in astronomy to measure large distances to objects outside our solar system, approximately equal to 3.26 light-years.

Conductivity is the measure of a material's ability to conduct electric current, and its unit is the mho, which is the reciprocal of the ohm (unit of resistance).

The magnetic field inside the core of a toroid depends on both the current flowing through the coil and the number of turns per unit length. According to Ampère's law, the magnetic field at a radius r inside the toroid is given by B = (μ * N * I) / (2πr), where N is the total number of turns, I is the current, and μ is the permeability of the core material. Thus, the magnetic field depends on the current and the number of turns, not just one or the other. The field is not zero inside the toroid; it is confined within the core region and varies with radius.

Raindrops fall through the air and reach a terminal velocity that depends on their size and shape, so different droplets have different ultimate velocities. This is why option A is correct.

The escape velocity from Earth's surface is approximately 11.2 kilometers per second, which converts to about 7 miles per second. This is the minimum speed needed for an object to escape Earth's gravitational pull without further propulsion. The other options (22, 15, and 12 miles per second) are higher than the actual escape velocity. Therefore, the correct answer is D (7 miles per second).

Electrons are the charge carriers in metals because they are loosely bound to atoms and can move freely, unlike protons which are tightly bound in the nucleus. Their small size and negative charge are true but not the primary reason for their mobility in metals.

A dioptre is the unit of measurement for the optical power of a lens or curved mirror, which is the reciprocal of the focal length measured in meters. Therefore, it measures lens refractive power.

The escape velocity from Earth is approximately 11.2 miles per second, which is closest to option C (12 miles/second). This is the minimum speed needed for a body to overcome Earth's gravitational pull without further propulsion.