Thermal | MCQs

Explanation

Railway tracks are made of steel, which expands in summer heat.

The gaps between rails allow space for this expansion, preventing the tracks from buckling or derailing trains.

Explanation

White clothes reflect most of the sunlight, which helps keep the body cooler compared to darker clothes, which absorb more heat.

Explanation

For water, the boiling point is 100ºC at a pressure of 1 atm

The boiling point of water decreases at higher altitudes due to Low atmospheric pressure

The boiling point of water increases with increased atmospheric pressure

The boiling point of water decreases with decreased atmospheric pressure

ND17-1-2023

Explanation

The transfer of thermal energy from one substance to another that requires no physical medium is called radiation.

Radiation is the process by which thermal energy (heat) is transferred through electromagnetic waves, such as infrared radiation. 

They can occur in a vacuum, such as in the transfer of heat from the Sun to the Earth.

Unlike conduction and convection, which require a physical medium (solids, liquids, or gases), 

Explanation

Jacobabad is called the thermal pole of Pakistan.

Jacobabad is one of the biggest cities of Pakistan.

Jacobabad is located in Sindh.

Explanation

Around 70% of the world's electricity is generated from thermal power plants, which use coal, natural gas, or oil to generate electricity.

This remains the dominant source of electricity worldwide despite the growing use of renewable energy.

Explanation

Speed of sound in air is proportional to the square root of absolute temperature v ∝ √T.

To double the speed, temperature must increase 4 times in Kelvin:

At 27°C = 300 K → 4 × 300 = 1200 K → 1200 - 273 = 927°C

Explanation

Copper, silver, aluminum, gold, steel, and brass are common conductors of electricity.

The most highly conductive metals are silver, copper, and gold

Silver is the first-best conductor of heat.

Copper is the second-best conductor of heat.

Explanation

China's experimental nuclear fusion reactor, known as the "artificial sun,"

It has reportedly achieved temperatures

it has set a new world record after superheating a loop of plasma to temperatures five times hotter than the sun 

Explanation

dielectric, insulating material, or a very poor conductor of electric current. 

When dielectrics are placed in an electric field, practically no current flows in them because, unlike metals