46 practice sets · Page 3 of 3
What is the formula for calculating electric power?
Power = Voltage × Current
Power = Current / Voltage
Power = Voltage / Current
Power = Current × Current
Correct Answer: A — Power = Voltage × Current
Explanation:
Electric power is calculated using Power = Voltage × Current. This shows how much energy is consumed or generated per unit of time in an electrical circuit.
Which of the following is a vector quantity?
Time
Distance
Speed
Velocity
Correct Answer: D — Velocity
Explanation:
Velocity is a vector quantity because it has both magnitude (speed) and direction. Speed has only magnitude and is a scalar quantity.
What is the main cause of refraction of light?
Change in wavelength of light
Change in color of light
Change in speed of light
Change in angle of incidence
Correct Answer: C — Change in speed of light
Explanation:
Refraction occurs when light passes from one medium to another, causing a change in speed, which results in the bending of light. It is most noticeable when light moves from air into water or glass.
What is the law of reflection?
Angle of incidence + Angle of reflection = 90°
Angle of incidence > Angle of reflection
Angle of incidence < Angle of reflection
Angle of incidence = Angle of reflection
Correct Answer: D — Angle of incidence = Angle of reflection
Explanation:
The law of reflection states that the angle at which light strikes a surface (angle of incidence) equals the angle at which it reflects (angle of reflection). This principle explains how mirrors work.
Which of the following is the formula for calculating speed?
Speed = Distance / Time
Speed = Time / Distance
Speed = Mass / Distance
Speed = Distance × Time
Correct Answer: A — Speed = Distance / Time
Explanation:
Speed is the distance travelled per unit of time. The formula is Speed = Distance / Time.
What is the speed of sound in air at room temperature?
150 m/s
340 m/s
1500 m/s
300 m/s
Correct Answer: B — 340 m/s
Explanation:
The speed of sound in air at room temperature (about 20°C) is approximately 340 metres per second. This speed varies with temperature and the medium through which sound travels.
