Explanation

• Light Year is the distance that light can travel in one year.
• The distance light travels in one year is known as light year.
• 1 light year is equal to 9.5 x 10¹²km.

Last verified on 30-03-2026

Explanation

Velocity is a vector quantity. 

A vector quantity has both magnitude and direction.

Velocity, which describes the rate of change of position in a specific direction, needs both a magnitude (speed) and a direction to be fully defined. 

Vector Quantities: Velocity, momentum, torque, acceleration.

Scalar Quantities: Work, distance, speed, mass.

Explanation

Biomass energy comes from plants, which get their energy through photosynthesis using sunlight.

So, the Sun is the original source of energy for all biomass.

Explanation

 Torque is the rotational analog of force and equals the rate of change of angular momentum.

Explanation

• The Candela (cd) is the SI unit of luminous intensity.
• It is defined as the luminous intensity of a monochromatic source that emits light at a frequency of 540 x 10^12 Hz with a luminous efficiency of 683 lm/W.

Explanation

The area under a force–displacement graph gives the work done by the force.

This is because Work = Force × Displacement, graphically represented by the area.

Explanation

The phrase “placed on the table” means the book is resting directly on the surface.

"On" correctly shows contact between the book and the table.

Explanation

The energy stored in a capacitor is given by U = (1/2)CV². If the potential difference (V) is doubled:

U ∝ V²

U' ∝ (2V)² = 4V²

So, the energy stored will increase by a factor of 4.

Explanation

Given the formula and calculation:

F = qE

= (1.6 × 10⁻¹⁹ C) × (1.8 × 10⁻⁸ N/C)

= 2.88 × 10⁻¹¹ N

Explanation

Electric field intensity is defined as force per unit charge (N/C) or potential difference per unit distance (V/m).

So, V/m is an equivalent.

It is commonly used unit for electric field intensity.