Physics - Comprehensive Mock Test 2

Question 11 Medium

Tape recorder should not be kept near one of the following things

A) Clock B) Magnet C) Electrical switchboard D) Radio

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Solution Breakdown:

The cassette tape contains a magnetic strip wound around two spools. Tiny magnetic particles are randomly scattered throughout the tape. A tape recorder should not be kept near a magnet as the latter can cause the magnetic material to be pushed and pulled out of place. Rearranging the magnetic particles erases the sound.

Question 12 Hard

An object at rest will remain at rest and an object in motion will remain in motion.until and unless it is acted upon by an external force. This is Newton's

A) First law B) Second law C) Third law D) Fourth law

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Solution Breakdown:

Newton's first law of motion - sometimes referred to as the law of inertia-states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force. This is normally taken as the definition of inertia.

Question 13 Medium

In the absence of ozone layer, Which rays will enter into atmosphere

A) Infrared B) Visible C) Ultraviolet D) X-rays

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Solution Breakdown:

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

Question 14 Medium

A spherical ball made of steel when dropped in mercury container will

A) sink in mercury B) will be on the surface of mercury C) will be partly immersed mercury D) will dissolve in mercury

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Solution Breakdown:

The density of steel usually ranges between 7.75 and 8.05 g/cm3 and the density of mercury is 13.534 g/cm3. Mercury is denser than steel this will mean that the buoyant force is large enough to float the steel ball. Different materials usually have different densities, so density is an important concept regarding buoyancy, purity and packaging.

Question 15 Medium

Radio waves, microwaves, infra-red spectrum, ultraviolet rays, X-rays and gamma rays are classified as ______

A) light waves B) electromagnetic waves C) electric waves D) magnetic waves

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Solution Breakdown:

Electromagnetic radiation is the radiant energy released by certain electromagnetic processes. It consists of electromagnetic waves which are synchronized oscillations of electric and magnetic fields that propagate at the speed of light through a vacuum.

Question 16 Easy

The fourth state of matter is known as

A) Gas B) Vapour C) Plasma D) Electrons

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Solution Breakdown:

The characteristics of plasmas are significantly different from those of ordinary neutral gases so that plasmas are considered a distinct "fourth state of matter, plasma is a state of matter similar to gas in which a certain portion of the particles is ionized. Heating a gas may ionize its molecules or atoms (reduce or increase the number of electrons in them), thus turning it into a plasma, which contains charged particles: positive ions and negative electrons or ions.

Question 17 Medium

Which among the following waves is used for communication by artificial satellites

A) Micro waves B) Radio waves C) A. M. D) Frequency of 1016 series

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Solution Breakdown:

For fixed (point-to-point) services, communications satellites provide a microwave radio relay technology complementary to that of communication cables. They are also used for mobile applications such as communications to ships, vehicles, planes and hand-held terminals, and for TV and radio broadcasting. Microwave technology is extensively used for point-to-point telecommunications (i.e., non broadcast uses).

Question 18 Medium

Water is not suitable as a calorimetric substance because it

A) has high specific heat B) is a good conductor C) has high boiling point D) low latent heat of vaporization

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Solution Breakdown:

The specific heat of water is higher than all other common substances. Hence, water is used for heating purposes (as in hot water bottles) and for cooling purposes (as in radiators of cars). Off all the liquids, mercury has the lowest specific heat due to which it is used as a thermometric liquid.

Question 19 Medium

Minimum numbers of unequal vectors which can give zero resultant are

A) Two B) Three C) Four D) More than four

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Solution Breakdown:

Minimum number of unequal vectors which can give three zero resultants.

Question 20 Medium

Two rods, one of copper and other of steel, experience the same up thrust when placed in water. Thus, both have

A) equal volume B) equal weight C) equal density D) equal mass

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Solution Breakdown:

When a body is placed in water, the upthrust or buoyant force acting on it depends upon the following factors: (1) Volume of the body submerged in the liquid - (V), or volume of the liquid displaced - (V); (ft) Density of the liquid - (d); and (Hi) Acceleration due to gravity In-line.