General Science Physics MCQ-7

Some common mediums in which_. speed of sound waves is measured are mentioned below.
1. Air
Steel
3. Copper
4. Water What is the correct increasing order of the speed of sound?

(A) 1 < 4 < 2 < 3
(B) 4 < 1 < 2 < 3
(C) 1 < 4 < 3 < 2
(D) 4 < 1 < 3 < 2

In order that a floating object be in stable equilibrium, its centre of buoyancy

(A) should be vertically below its centre of gravity
(B) should be horizontal in line with its centre of gravity
(C) should be vertically above its centre of gravity
(D) may be anywhere

Consider the following statements
1. Modulus of rigidity or shear modulus of elasticity (G) is defined as the ratio of tangential stress to the shearing strain, within the elastic limit.
2. The SI unit of modulus of rigidity is NrrT2 or Pascal.
3. Modulus of rigidity is involved with solids only.
Which of the statement(s) given above is/are correct?

(A) 1,2 and 3
(B) 2 and 3
(C) 1 and 3
(D) 1 and 2

Speed of electromagnetic wave is the same

(A) for all frequencies
(B) for all wavelengths
(C) in all media
(D) for all intensities

Lactometer is a form of hydrometer used to measure the purity of milk. If in milk, the lactometer sinks up to the mark of 1, which one of the following conclusions can be drawn?

(A) The milk in the liquid is only 50% pure
(B) The milk in the liquid is only( 3/4)th of it
(C) The milk in the liquid is only (1/4)th of it (25% pure)
(D) The milk is 100% pure

Consider the following statements
1. Quartz and phosphor bronze are the examples of nearly perfectly elastic bodies.
2. Putty, mud and paraffin wax are the examples of perfectly plastic bodies.
Which of the statement(s) given above are correct?

(A) Only 1
(B) Only 2
(C) Both 1 and 2
(D) Neither 1 nor 2

Sound moves with higher velocity if

(A) pressure of the medium is decreased
(B) temperature of the medium is increased
(C) humidity of the medium
(D) Both (b) and (c)

Consider the following statements
When an object floats inside a liquid, then
1. The apparent weight of the object is equal to the liquid displaced by the object.
2. The centre of gravity (CG) of the object and the centre of gravity (CG) of the displaced water lie in the same vertical line.
Which of the above statement(s) given above is/are correct?

(A) Only 1
(B) Only 2
(C) Both 1 and 2
(D) Neither 1 nor 2

Which is more elastic?

(A) Aluminium
(B) Copper
(C) Iron
(D) Glass

Radar waves are sent towards a moving aero plane and the reflected waves are received. When the aero plane is moving towards the radar, the wavelength of the wave

(A) decreases
(B) increases
(C) remains the same
(D) sometimes increases or decreases

Consider the following statements
1. The density of water is maximum at 50,C.
2. The hydrometer is a device through which the density of fluids (liquid or gas) is measured.
Which of the above statement(s) given above is/are correct?

(A) Only 1
(B) Only 2
(C) Both 1 and 2
(D) Neither 1 nor 2

The breaking stress of wire depends on

(A) material of the wire
(B) length of the wire
(C) radius of the wire
(D) shape of the cross-section of the wire

Consider the following statements
1. Microwave ovens are used for cooking purposes.
2. Microwaves are used in Radar system for aircraft navigation.
3. A radar using microwave can help in detecting the seed of tennis ball, cricket ball, automobile while in motion.
Which of the statements given above are correct?

(A) 2 and 3
(B) 1 and 2
(C) 1 and 3
(D) 1, 2 and 3

Consider the following statements The fraction of a ball floating inside the liquid depends upon
1. density of the liquid
2. mass of the ball
3. density of the ball
Which of the statements given above are correct?

(A) 1 and 2
(B) 2 and 3
(C) 1 and 3
(D) 1, 2 and 3

The SI unit of elastic potential energy is

(A) watt
(B) joule
(C) joule s
(D) joule s

The quality of a musical note depends upon

(A) it s frequency
(B) it s amplitude
(C) the wave velocity
(D) its harmonic content

Assertion (A) The ships of iron and the boats of wood float in water but the nails iron sink,
Reason (R) The special design and shape of the ship and the boat through which weight of displaced water are more than the weight of the ship and boat, due to which more force of buoyancy becomes operative and the ships or boats floats. But the weight of the water displaced by the nails is less than the weight of nails that is why nails sink.

(A) Both A and R are individually true, but’ R is the correct explanation of A
(B) Both A and R are individually true and R is not the correct explanation of A
(C) A is true but R is false
(D) A is false but R is true