Explanation

• Power is the rate of doing work or the rate at which energy is transferred.
• It is a scalar quantity (has magnitude only).
• It shows how quickly work is done.
• The SI unit of power is the Watt (W).
• 1 Watt = 1 Joule per second (1 W = 1 J/s).

Additional information:

• Formula: P = W/t = E/t
• SI Base Unit: kg·m²·s⁻³
• Dimension Formula: ML²T⁻³
• James Watt is the scientist after whom the Watt unit is named.

Last verified on 09-07-2026

Explanation

• Displacement is the straight-line change in position from an initial point to a final point.
• It is a vector quantity, having both magnitude and direction.

Last verified on 31-10-2026

Explanation

• Newton's second law defines force as the product of mass and acceleration.
• The net force acting on an object determines its acceleration.
• It also explains that force is equal to the rate of change of momentum.

Last verified on 31-10-2026

Explanation

• At the center of the Earth, g = 0.
• Gravity from all directions cancels out at the center.
• So net gravitational force becomes zero.
• An object would feel weightless there.
• This is due to symmetrical distribution of Earth's mass.
• Earth’s surface gravity: 9.8 m/s²

Last verified on 17-06-2026

Explanation

• All electromagnetic waves travel through a vacuum at 3x10^8 m/s.
• This is the speed of light (c).
• Radio waves, microwaves, visible light, X-rays and gamma rays all have the same speed in vacuum.

Last verified on 31-10-2026

Explanation

• Earth's magnetic field varies in both strength (magnitude) and direction from place to place.
• Its direction changes with geographic location and is not the same at the magnetic equator and poles.
• Its strength is generally weaker near the magnetic equator and stronger near the magnetic poles.

Last verified on 31-10-2026

Explanation

• Salmonella Typhi is the bacterium responsible for typhoid fever.
• It is a Gram-negative, rod-shaped bacterium.
• It spreads through food or water contaminated with the feces of an infected person.
• Common symptoms include prolonged fever, headache, weakness, abdominal pain, and digestive problems.
• Typhoid can be prevented through safe drinking water, proper sanitation, handwashing, and vaccination.

Last verified on 31-10-2026

Explanation

• Hemophilia is an inherited bleeding disorder caused by deficiency or dysfunction of blood-clotting factors.
• Hemophilia A is caused by deficiency of clotting Factor VIII.
• Hemophilia B is caused by deficiency of clotting Factor IX.
• These factors are essential for normal blood clot formation.
• Common symptoms include prolonged bleeding, easy bruising, and bleeding into joints and muscles.

Last verified on 31-10-2026

Explanation

• The hypothalamus acts as the body's temperature-regulating center.
• When core body temperature rises, it triggers vasodilation of blood vessels near the skin.
• Vasodilation increases blood flow to the skin, allowing more heat to escape.
• Sweating helps cool the body through evaporation of sweat from the skin.

Last verified on 31-10-2026

Explanation

• The term carbohydrate comes from the idea of “hydrated carbon.”
• In many simple carbohydrates, hydrogen and oxygen occur in an approximate 2:1 atomic ratio, the same ratio found in water (H₂O).
• For example, glucose has the molecular formula C₆H₁₂O₆, with 12 hydrogen atoms and 6 oxygen atoms.

Last verified on 31-10-2026