The ozone layer is a layer in Earth’s atmosphere containing relatively high concentrations of ozone (O3). The layer absorbs 97–99% of the Sun’s mediumfrequency ultraviolet light (from about 200 nm to 315 nm wavelength), which potentially damages exposed life forms on Earth.

Correct Option: C

The ozone layer is a layer in Earth’s atmosphere containing relatively high concentrations of ozone (O3). The layer absorbs 97–99% of the Sun’s mediumfrequency ultraviolet light (from about 200 nm to 315 nm wavelength), which potentially damages exposed life forms on Earth.

When Soaps and detergents are added to water, they weaken the strength of the skin on the water’s surface due to surface tension by interfering with hydrogen bonding between water molecules. It happens because the polar end of the soap or detergent is also attracted to the water, thereby decreasing the surface tension.

Correct Option: B

When Soaps and detergents are added to water, they weaken the strength of the skin on the water’s surface due to surface tension by interfering with hydrogen bonding between water molecules. It happens because the polar end of the soap or detergent is also attracted to the water, thereby decreasing the surface tension.

Earth attracts all bodies towards its centre. The acceleration produced in the body due to attraction force of earth on it is called the acceleration due to gravity. A astronaut in a satellite experiences weightlessness because two forces act on him: gravitational pull and centrifugal force which cancel out each other with the resultant force acting on him being zero.

Correct Option: A

Earth attracts all bodies towards its centre. The acceleration produced in the body due to attraction force of earth on it is called the acceleration due to gravity. A astronaut in a satellite experiences weightlessness because two forces act on him: gravitational pull and centrifugal force which cancel out each other with the resultant force acting on him being zero.

A solar cell (also called a photovoltaic cell) is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect. It is a form of photoelectric cell (in that its electrical characteristics—e.g. current, voltage, or resistance— vary when light is incident upon it) which, when exposed to light, can generate and support an electric current without being attached to any external voltage source.

Correct Option: B

A solar cell (also called a photovoltaic cell) is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect. It is a form of photoelectric cell (in that its electrical characteristics—e.g. current, voltage, or resistance— vary when light is incident upon it) which, when exposed to light, can generate and support an electric current without being attached to any external voltage source.

A head mirror is mostly used for examination of the ear, nose & throat. It comprises a circular concave mirror, with a small hole in the middle, and is attached to a head band. The mirror is worn over the physician’s eye of choice, with the concave mirror surface facing outwards and the hole directly over the physician’s eye, providing illumination like a ring light.

Correct Option: A

A head mirror is mostly used for examination of the ear, nose & throat. It comprises a circular concave mirror, with a small hole in the middle, and is attached to a head band. The mirror is worn over the physician’s eye of choice, with the concave mirror surface facing outwards and the hole directly over the physician’s eye, providing illumination like a ring light.