Explanation

• A black box is a flight recorder used in aircraft.
• It records important flight data and cockpit audio.
• It helps investigators determine the causes of aircraft accidents or incidents.
• The two main types are Flight Data Recorder (FDR) and Cockpit Voice Recorder (CVR).

Last verified on 05-10-2026

Explanation

• Watt (W) is the SI unit of power, while kilowatt (kW) is also a unit of power.
• 1 kilowatt = 1,000 watts.
• Power indicates the rate at which energy is used or transferred.

Additional information:

• Kilowatt-hour (kWh) is a unit of electrical energy.

Last verified on 05-10-2026

Explanation

The least count of a Vernier caliper is 0.1 mm (or 0.01 cm).

It is the smallest measurement that can be accurately read using the instrument.

It is derived from the difference between one main scale reading and one Vernier scale reading.

It is commonly used to accurately measure outside diameters of shafts, thicknesses of various parts, diameters of holes or rings, internal dimensions of hollow jobs, and depths of holes or steps. 

Explanation

• The SI unit of energy is the Joule (J).
• It is the unit of energy, work, and heat.

Additional information:

• 1 Joule (J) = 1 Newton × 1 meter
• Calorie – 1 cal = 4.184 J
• Kilowatt-hour (kWh) – 1 kWh = 3.6 × 10⁶ J
• Electronvolt (eV) – 1 eV ≈ 1.602 × 10⁻¹⁹ J
• Erg (CGS unit) – 1 erg = 10⁻⁷ J

Last verified on 17-01-2026

Explanation

• Earth’s gravity provides the force that keeps satellites in orbit.
• This gravitational force pulls the satellite toward Earth.
• The satellite’s forward motion makes it continuously fall around Earth rather than directly into it.
• Newton’s Law of Gravitation explains this gravitational attraction.