Physics Online Quiz

Water and petrol are immiscible with each other and petrol which forms the upper layer continues to burn. Water is heavier than petrol, petrol will come above the water and continue the contact with the atmosphere (oxygen).

A satellite in vacuum does not require any energy for orbiting. A satellite orbits Earth when its speed is balanced by the pull of Earth's gravity. The gravitational force between the earth and the satellite provides the necessary centripetal force to move around the earth.

Hypermetropia, also known as long-sightedness, is a defect of vision in which a person can't see the nearby object clearly (appears blurred), though can see the distant objects clearly. The near point of a hypermetropic eye is greater than 25 cm.

Humidity is a measure of the amount of water vapour in the air. Relative humidity measures the amount of water in the air in relation to the maximum amount of water vapour (moisture). The higher the temperature, the more water vapour the air can hold.

All objects, regardless of mass, will fall at the same rate. Heavier things have a greater gravitational force AND heavier things have a lower acceleration. It turns out that these two effects exactly cancel to make falling objects have the same acceleration regardless of mass.

Teletext is a standard for displaying text and graphics on the TV screen. Teletext sends data in the broadcast signal, hidden in the invisible vertical blanking interval area at the top and bottom of the screen.

Mesons are hadronic subatomic particles composed of an equal number of quarks and antiquarks, usually one of each, bound together by strong interactions. Outside the nucleus, mesons appear in nature only as short-lived products of very high-energy collisions between particles made of quarks, such as cosmic rays (high-energy protons and neutrons) and baryonic matter.

As per WHO The standard audible capacity of a healthy human being is in the range of 45-50 decibels. Humans can hear sounds between 0 and 180 decibels. To be precise, noise becomes harmful when it exceeds 75 decibels (dB) and is painful above 120 dB.

When a piece of wood is held underwater, the up-thrust on it will be less than the weight of the wood. Here, the wooden piece is under the water because the up-thrust force acting on the wood under the water is less than the weight of the wooden piece.

The word “laser” is an acronym for “light amplification by stimulated emission of radiation”. It was invented by the American engineer and physicist Theodore Harold Maiman in 1960.