Gravitation — JEE physics STD 12 Science — Question

Assertion : lt is better to wash the clothes in cold soap solution.
Reason : The surface tension of cold solution is more than the surface tension of hot solution.

Assertion : The speed of satellite always remains constant in an orbit.
Reason : The speed of a satellite depends on its path.

Assertion : Short wave bands are used for transmission of ratio waves to a large distance
Reason : Short waves are reflected by ionosphere

Assertion : Two similar trains are moving along the equatorial line with the same speed but in opposite direction. They will exert equal pressure on the rails.
Reason : In uniform circular motion the magnitude of acceleration remains constant but the direction continuously changes.

Assertion : A narrow pulse of light is sent through a medium. The pulse will retain its shape as it travels through the medium.
Reason : A narrow pulse is made of harmonic waves with a large range of wavelengths.

Assertion : Water kept in an open vessel will quickly evaporate on the surface of the moon.
Reason : The temperature at the surface of the moon is much higher than boiling point of the water.

Assertion : Density is a derived physical quantity.
Reason : Density cannot be derived from the fundamental physical quantities.

Assertion : Magnetism is relativistic.
Reason : When we move along with the charge so that there is no motion relative to us, we find no magnetic field associated with the charge.

Assertion : Thin films such as soap bubble or a thin layer of oil on water show beautiful colours when illuminated by white light.
Reason : It happens due to the interference of light reflected from the upper surface of the thin film.

Assertion : Capacitor serves as a block for dc and offers an easy path to ac.
Reason : Capacitive reactance is inversely proportional to frequency.