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Question (1)

QN0035574

Modulus of rigidity of ideal liquids is

(A)
infinity
(B)
zero
(C)
unity
(D)
some finite small non-zero constant value

Correct Answer: B

Explanation:

As liquid is ideal so no. frictional force exists hence, tangential forces are zero so there is no stress developed.

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Question (2)

QN0035575

The maximum load a wire can withstand without breaking, when its length is reduced to half of its original length, will

(A)
be double
(B)
be half
(C)
be four times
(D)
remain same

Correct Answer: D

Explanation:

As we know that,

Breaking force

Breaking stress

When length of the wire changes (or by reducing half) area of cross-section remains same.

Hence, breaking force will be same because breaking stress does not depend on length.

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Question (3)

QN0035576

The temperature of a wire is doubled. The Young's modulus of elasticity

(A)
will also double
(B)
will remain same
(C)
will become four times
(D)
will decrease

Correct Answer: D

Explanation:

As we know that, length of a wire when the temperature increased

where is change in the temperature.

is original length,

is coefficient of linear expansion and

is length at temperature .

Now,

Now, Young's modulus

As,

So, if temperature increass increases, hence Young's modulus of elasticity decreases.

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Question (4)

QN0035577

A spring is stretched by applying a load to its free end. The strain produced in the spring is

(A)
volumetric
(B)
shear
(C)
longitudinal and shear
(D)
longitudinal

Correct Answer: C

Explanation:

When a spring is stretched by applying a load to its free end. Clearly the length and shape of the spring changes. So strain produced when change in length corresponds to longitudinal strain and change in shape corresponds to shearing strain.

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Question (5)

QN0035578

A rigid bar of mass is supported symmetrically by three wires each of length . Those at each end are of copper and the middle one is of iron. The ratio of their diameters, if each is to have the same tension, is equal to

(A)
(B)
(C)
(D)

Correct Answer: B

Explanation:

As we know that,

The Young's modulus

If and are constants. So,

Hence, we can find ratio as

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Question (6)

QN0035579

A mild steel wire of length and cross-sectional area is stretched, well within elastic limit, horizontally
between two pillars (figure). A mass is suspended from the mid-point of the wire. Strain in the wire is

(A)
(B)
(C)
(D)

Correct Answer: A

Explanation:

Consider the given diagram

So, change in length

.

Strain

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Question (7)

QN0035580

A rectangular frame is to be suspended symmetrically by two strings of equal length on two supports
(figure). It can be done in one of the following three ways;
The tension in the strings will be

(A)
the same in all cases
(B)
least in (a)
(C)
least in (b)
(D)
least in (c)

Correct Answer: C

Explanation:

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Question (8)

QN0035581

Consider two cylindrical rods of identical dimensions, one of rubber and the other of steel. Both the rods are fixed rigidly at one end to the roof. A mass is attached to each of the free ends at the centre of the rods.

(A)
Both the rods will elongate but there shall be no perceptible change in shape
(B)
The steel rod will elongate and change shape but the rubber rod will only elongate
(C)
The steel rod will elongate without any perceptible change in shape, but the rubber rod will elongate and the shape of the bottom edge will change to an ellipse
(D)
The steel rod will elongate, without any perceptible change in shape, but the rubber rod will elongate with the shape of the bottom edge tapered to a tip at the centre

Correct Answer: D

Explanation:

A mass is attached at the centre or midpoint of rod of rubber and steel. As the mass is attached to both the rods, both rod will be elongated as shown in figures but due to different elastic properties of

material rubber changes shape also. (Rubber) (Steel) As the Young's modulus of rigidity for steel, is larger than rubber, so strain for rubber is larger than steel for same stress.

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Question (1)

Modulus of rigidity of ideal liquids is

Explanation:

Link:

Question (2)

The maximum load a wire can withstand without breaking, when its length is reduced to half of its original length, will

Explanation:

Link:

Question (3)

The temperature of a wire is doubled. The Young's modulus of elasticity

Explanation:

Link:

Question (4)

A spring is stretched by applying a load to its free end. The strain produced in the spring is

Explanation:

Link:

Question (5)

A rigid bar of mass is supported symmetrically by three wires each of length . Those at each end are of copper and the middle one is of iron. The ratio of their diameters, if each is to have the same tension, is equal to

Explanation:

Link:

Question (6)

A mild steel wire of length and cross-sectional area is stretched, well within elastic limit, horizontally
between two pillars (figure). A mass is suspended from the mid-point of the wire. Strain in the wire is

Explanation:

Link:

Question (7)

A rectangular frame is to be suspended symmetrically by two strings of equal length on two supports
(figure). It can be done in one of the following three ways;
The tension in the strings will be

Explanation:

Link:

Question (8)

Consider two cylindrical rods of identical dimensions, one of rubber and the other of steel. Both the rods are fixed rigidly at one end to the roof. A mass is attached to each of the free ends at the centre of the rods.

Explanation:

Link:

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Question (1)

Modulus of rigidity of ideal liquids is

Explanation:

Link:

Question (2)

The maximum load a wire can withstand without breaking, when its length is reduced to half of its original length, will

Explanation:

Link:

Question (3)

The temperature of a wire is doubled. The Young's modulus of elasticity

Explanation:

Link:

Question (4)

A spring is stretched by applying a load to its free end. The strain produced in the spring is

Explanation:

Link:

Question (5)

A rigid bar of mass is supported symmetrically by three wires each of length . Those at each end are of copper and the middle one is of iron. The ratio of their diameters, if each is to have the same tension, is equal to

Explanation:

Link:

Question (6)

A mild steel wire of length and cross-sectional area is stretched, well within elastic limit, horizontally between two pillars (figure). A mass is suspended from the mid-point of the wire. Strain in the wire is

Explanation:

Link:

Question (7)

A rectangular frame is to be suspended symmetrically by two strings of equal length on two supports (figure). It can be done in one of the following three ways;The tension in the strings will be

Explanation:

Link:

Question (8)

Consider two cylindrical rods of identical dimensions, one of rubber and the other of steel. Both the rods are fixed rigidly at one end to the roof. A mass is attached to each of the free ends at the centre of the rods.

Explanation:

Link:

Excel With Tutors

ExcelWithTutors

For Student

For Tutors

Learn

OUR POLICY

A mild steel wire of length and cross-sectional area is stretched, well within elastic limit, horizontally
between two pillars (figure). A mass is suspended from the mid-point of the wire. Strain in the wire is

A rectangular frame is to be suspended symmetrically by two strings of equal length on two supports
(figure). It can be done in one of the following three ways;
The tension in the strings will be