Explanation

Sputnik-1, launched by the Soviet Union in 1957, was the first artificial satellite to orbit the Earth.

It marked the beginning of the space age and the start of space exploration.

Explanation

Pressure is inversely proportional to area (Pressure = Force / Area), and the pointed end has a much smaller area.

Thus, the same force produces greater pressure at the pointed end, allowing it to pierce surfaces easily.

Explanation

MRI provides detailed images of soft tissues and tiny internal structures using strong magnetic fields and radio waves.

It is highly effective for diagnosing issues in the brain, spinal cord, joints, and internal organs.

Explanation

Natural disasters such as earthquakes, volcanic eruptions, and floods can alter the Earth's surface, changing the shape of the land.

These events can lead to the formation of new landforms or the destruction of existing ones.

Explanation

Polyisoprene is the synthetic version of natural rubber.

It has similar properties.

It is commonly used to make rubber products.

Explanation

Cations are positively charged ions. 

Cations are formed when a metal loses its electrons.

Explanation

A circuit is a closed path through which electrons (electric current) flow.

It typically includes components like resistors, batteries, and wires, allowing controlled movement of current.

Explanation

Petroleum has the highest energy density among fossil fuels, making it the richest source of energy.

It is widely used in transportation, industry, and power generation due to its high calorific value.

Explanation

Gravitational force (F) is given by:

F ∝ (m1 * m2) / r²

If both masses (m1 and m2) are halved:

New force F' ∝ ((m1/2) * (m2/2)) / r²

F' ∝ (m1 * m2) / (4 * r²)

F' = F / 4

The gravitational force becomes one fourth.

Explanation