A bulb intended to light a room takes 100 J of electrical energy per unit time. The efficiency of the bulb, if 30 J of the energy is converted to heat is:

A vector quantity has both magnitude and direction. A scalar quantity has only magnitude.

• A) Distance (scalar), Work done (scalar).
• B) Weight (vector), Temperature (scalar).
• C) Velocity (vector), Acceleration (vector).
• D) Speed (scalar), Mass (scalar). Option B correctly identifies a vector (weight) and a scalar (temperature).

The final answer is $\boxed{\text{B}}$

The International System of Units (SI) defines seven base units. These are meter (length), kilogram (mass), second (time), ampere (electric current), kelvin (thermodynamic temperature),