Explanation

RADAR is an acronym for Radio Detection and Ranging.

The system works by transmitting high-frequency radio waves, or microwaves (which are a type of radio wave), toward an object.

The waves bounce off the object, and a receiver in the radar system detects the reflected energy, known as an echo.

By measuring the time delay between sending and receiving the signal, the system can calculate the distance and velocity of the object. 

Explanation

Uranium-235 (U²³⁵) is a fissile isotope, meaning it readily undergoes nuclear fission when struck by a neutron.

It is commonly used in nuclear reactors and atomic bombs for this reason.

Explanation

Surface Tension:

"The property of the surface of a liquid that allows it to resist an external force,

due to the cohesive nature of its molecules."

Explanation

The density of air varies with height.

It is maximum near the surface of the earth and decreases as the height increases.

When we climb up a mountain,

the density of air decreases,

and thus the atmospheric pressure also decreases.

Explanation

• The scientist who first discovered that the earth revolves around the sun was Copernicus.
• Earth's Rotational Theory:
  • Rotation can be defined as the spin of Earth on its own axis from west to east direction.
  • It must also be noted that the speed of rotation of the earth is not constant throughout latitudes.
    
  • It differs at different latitudes.

Explanation

WALFORM stands for landforms created by the action of sea waves.

Examples include cliffs, arches, and sea caves formed by wave erosion.

Explanation

MRI (Magnetic Resonance Imaging) is used for detailed scanning of the brain.

It helps detect tumors, strokes, and other brain disorders accurately.

Explanation

Radius of circular path in magnetic field: r = mv / qB

Alpha particle (m = 4u, q = +2e) → r = 2 × r_proton → larger radius than proton.

Explanation

Cross product: A × B = |A||B| sinθ n̂

B is a scalar multiple of A → θ = 0° → sin0° = 0 → A × B = 0.

Explanation

One full revolution = 2π radians

Half revolution = 2π / 2 = π radians