Physics Online Quiz

Battery acid is sulphuric acid that has been diluted with water to attain a 30-40% concentration level.

In economics, economic equilibrium is a situation in which economic forces such as supply and demand (internal factors) are balanced and in the absence of external influences, the values of economic variables will not change.

Newton's First Law, sometimes referred to as the law of inertia, describes the influence of a balance of forces upon the subsequent movement of an object.

The period of oscillation of a simple pendulum is T=2π√(l/g). The value of g is less on the moon than that on the surface of the earth. So T increases. Hence, the time period of a pendulum when taken to the Moon would increase.

Aperture refers to the opening of a lens's diaphragm through which light passes. It controls the brightness of the image that passes through the lens and falls on the image sensor. The camera sensor size is one of the key elements that affect the sharpness of an image.

A parabolic concave mirror is used in torches and car headlamps as reflectors. This type of mirror is capable of directing the light at a particular point as they have converging power. These mirrors provide clear visibility.

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.

'Therm' is a non-SI unit of heat energy. 1 therm is equal to 100000 British thermal units (BTU).

ENIAC (Electronic Numerical Integrator and Computer) was the first programmable, electronic, general-purpose digital computer made in 1945 by the United States. ENIAC weighed over 30 tons with over 17,000 valves (vacuum tubes).

The shape of our milky way galaxy is spiral. The Milky Way is a huge collection of stars, dust and gas. It's called a spiral galaxy because if you could view it from the top or bottom, it would look like a spinning pin-wheel.