Q256. Assertion (A): A jet aircraft moving at Mach Number equal to 1 travels faster at an altitude of 15 km than while moving at Mach Number equal to 1 near the sea level. Reason (R): The velocity of sound depends on the temperature of the surrounding medium.

Assertion (A): A jet aircraft moving at Mach Number equal to 1 travels faster at an altitude of 15 km than while moving at Mach Number equal to 1 near the sea l

Assertion (A): With the increase of temperature, the viscosity of glycerine increases. Reason (R): Rise of temperature increases kinetic energy of molecules. Co

Assertion (A) : The amount of moisture in the atmosphere is related to latitude. Reason (R) : The capacity to hold moisture in the form of water vapour is relat

Assertion (A) : Thickness of the atmosphere is maximum over the Equator. Reason (R) : High insolation and strong convection currents occur over the Equator.

Assertion (A): The weight of a body decreases with the increase of altitude on earth. Reason (R): The earth is not a perfect sphere. Codes:

Assertion (A): Artificial satellites are always launched from the earth in the eastward direction. Reason (R): The earth rotates from west to east and so the sa

Assertion (A): A piece of copper and a piece of glass are heated to the same temperature. When touched, thereafter, the copper piece appears hotter than the gla

Assertion (A): A man standing on a completely frictionless surface can propel himself by whistling. Reason (R): If no external force acts on a system, its momen

Assertion (A): The boiling point of water decreases as the altitude increases. Reason (R): The atmospheric pressure increases with altitude. Codes: (a) Both A a

Assertion (A): Small glass beads fixed on traffic signals glow brightly when light falls upon them. Reason (R): Light is totally reflected when the angle of inc

Assertion (A): In a motion picture, usually 24 frames are projected every second over the whole length of the film. Reason (R): An image formed on the retina of

Assertion (A) : Wind patterns are clockwise in the Northern Hemisphere and anti-clockwise in the Southern Hemisphere. Reason (R) : The directions of wind patter

Assertion (A): Radio waves bend in a magnetic field. Reason (R): Radio waves are electromagnetic in nature.

Assertion (A): Radio waves bend in a magnetic field. Reason (R): Radio waves are electromagnetic in nature.

Assertion (A): Large cold storage plants use ammonia as refrigerant while domestic refrigerators use chlorofluoro- carbons. Reason (R): Ammonia can be liquefied

Assertion (A) : 60° - 65° latitudes in both the hemispheres have a low pressure belt instead of high pressure. Reason (R) : The low pressure areas are permanent

Assertion (A): Areas lying within five to eight degrees latitude on either side of the equator receive rainfall throughout the year. Reason (R): High temperatur

Assertion (A): An iron ball floats on mercury but gets immersed in water. Reason (R): The specific gravity of iron is more than that of mercury. Codes:

Given below are two statements one labelled as Assertion (A) and the other labelled as Reason (R). Assertion (A) : Areas near the equator receive rainfall throu

Assertion (A) : The surface winds spiral inwards upon the centre of the cyclone. Reason (R) : Air descends in the centre of the cyclone.

Assertion (A) : The same face of the moon is always presented to the earth. Reason (R) : The moon rotates about its own axis in 23 and half days which is about

Assertion (A): Transformer is useful for stepping up or stepping down voltages. Reason (R): Transformer is a device used in D.C. circuits. In the context of the

Assertion (A): To dilute sulphuric acid, acid is added to water and not water to acid. Reason (R): Specific heat of water is quite large.

Assertion (A) : Anticyclonic conditions are formed in the winter season when atmospheric pressure is high and air temperatures are low. Reason (R) : Winter rain

Assertion (A): The temperature of a metal wire rises when an electric current is passed through it. Reason (R): Collision of metal atoms with each other release

Assertion (A) : Existence of human life on Venus is highly improbable. Reason (R): Venus has extremely high level of carbon dioxide in its atmosphere.

Assertion (A): To orbit around the Sun the planet Mars takes lesser time than the time taken by the earth. Reason (R): The diameter of the planet Mars is less t

Assertion (A) : During the neap tides. The high tide is lower and the low tide is higher than usual. Reason (R) : The neap tide, unlike the spring tide, occurs

Consider the following statements in respect of a jet engine and a rocket: 1. A jet engine uses the surrounding air for its oxygen supply and so is unsuitable f

Which one of the following types of waves are used in a night vision apparatus?

Consider the following statements: 1. If magenta and yellow coloured circles intersect, the intersected area will have red colour. 2. If cyan and mage

Consider the following statements : 1. A flute of smaller length produces waves of lower frequency. 2. Sound travels in rocks in the form of longitudi

In which one among the following is the speed of sound maximum?

Diffusion of light in the atmosphere takes place due to:

Which one of the following statements is not correct?

Consider the following statements: 1. Light of longer wavelengths is scattered much more than the light of shorter wavelength. 2. The speed of visible

Consider the following natural phenomena: 1. Terrestrial heating 2. Reflection of light 3. Refraction of light 4. Diffraction of light Due to which o