Explanation

• Starlight passes through Earth’s atmosphere.
• Different air layers have different densities and temperatures.
• Light is repeatedly refracted (bent).
• This causes the star’s brightness to appear to change rapidly.
• This apparent change is called twinkling (scintillation).

Last verified on 26-10-2026

Explanation

Given:

M = 6.42 x 10^23 kg

R = 3370 km = 3.37 x 10^6 m

G = 6.67 x 10^-11 Nm2/kg2

Formula: g = G x M / R^2

g = 6.67 x 10^-11 x 6.42 x 10^23 / (3.37 x 10^6)^2

g = 4.282 x 10^13 / 1.135 x 10^13

g = 3.77 m/s2

Last verified on 26-10-2026

Explanation

• Power is the rate at which work is done or energy is transferred.
• Its SI unit is the watt (W).
• British thermal unit per hour (BTU/h), horsepower (hp), and watt are units of power.
• A newton-meter (N·m) is the unit of work or energy, equivalent to one joule (J).
• It is not a unit of power.

Last verified on 26-10-2026

Explanation

• The normal body temperature is: 37°C.
• The average normal body temperature is generally accepted as 98.6°F (37°C).
• A temperature over 100.4°F (38°C) means you have a fever.

Additional Information:

• Hypothermia is the term used for temperature less than 36.50°C.
• Mild Pyrexia is the term used for temperature (99-100°F).
• Moderate Pyrexia is the term used for temperature (100-103°F).
• Severe Pyrexia is the term used for temperature (103-105°F).

Explanation

Explanation

• A body is in equilibrium when the net force acting on it is zero.
• According to Newton's second law, zero net force means zero acceleration.
• A body in equilibrium may be at rest or move with constant velocity.
• Both linear acceleration and angular acceleration must be zero for complete mechanical equilibrium.

Last verified on 26-10-2026

Explanation

• The rate of change in displacement is referred to as velocity.
• The velocity of an object generally changes during its motion.
• The change in position is known as displacement.
• The maximum displacement from the mean position is called amplitude.

Last verified on 26-10-2026

Explanation

• A pair of unlike parallel forces (forces that act in opposite directions) with different lines of force produce a couple.
• It is also known as a moment or torque.
• This is a rotational force that tends to cause rotation around a pivot point or axis.

Last verified on 26-10-2026

Explanation

• Newton's second law states that the rate of change of momentum is directly proportional to the applied net force and occurs in the direction of that force.
• The mathematical form is F = Δp / Δt, where p represents momentum.
• For constant mass, the law is commonly written as F = ma.

Last verified on 26-10-2026

Explanation