JEE Main 2021 (Online) 31st August Evening Shift | Properties of Matter Question 65 | Physics

JEE Main 2021 (Online) 31st August Evening Shift

MCQ (Single Correct Answer)

-1

Four identical hollow cylindrical columns of mild steel support a big structure of mass 50 $$\times$$ 10³ kg. The inner and outer radii of each column are 50 cm and 100 cm respectively. Assuming uniform local distribution, calculate the compression strain of each column. [Use Y = 2.0 $$\times$$ 10¹¹ Pa, g = 9.8 m/s²]

3.60 $$\times$$ 10^$$-$$8

2.60 $$\times$$ 10^$$-$$7

1.87 $$\times$$ 10^$$-$$3

7.07 $$\times$$ 10^$$-$$4

JEE Main 2021 (Online) 31st August Evening Shift

MCQ (Single Correct Answer)

-1

A bob of mass 'm' suspended by a thread of length l undergoes simple harmonic oscillations with time period T. If the bob is immersed in a liquid that has density $${1 \over 4}$$ times that of the bob and the length of the thread is increased by 1/3^rd of the original length, then the time period of the simple harmonic oscillations will be :-

$${3 \over 2}$$T

$${3 \over 4}$$T

$${4 \over 3}$$T

JEE Main 2021 (Online) 31st August Morning Shift

MCQ (Single Correct Answer)

-1

A uniform heavy rod of weight 10 kg ms^$$-$$2, cross-sectional area 100 cm² and length 20 cm is hanging from a fixed support. Young modulus of the material of the rod is 2 $$\times$$ 10¹¹ Nm^$$-$$2. Neglecting the lateral contraction, find the elongation of rod due to its own weight.

2 $$\times$$ 10^$$-$$9 m

5 $$\times$$ 10^$$-$$8 m

4 $$\times$$ 10^$$-$$8 m

5 $$\times$$ 10^$$-$$10 m

JEE Main 2021 (Online) 27th August Morning Shift

MCQ (Single Correct Answer)

-1

In Millikan's oil drop experiment, what is viscous force acting on an uncharged drop of radius 2.0 $$\times$$ 10^$$-$$5 m and density 1.2 $$\times$$ 10³ kgm^$$-$$3 ? Take viscosity of liquid = 1.8 $$\times$$ 10^$$-$$5 Nsm^$$-$$2. (Neglect buoyancy due to air).

3.8 $$\times$$ 10^$$-$$11 N

3.9 $$\times$$ 10^$$-$$10 N

1.8 $$\times$$ 10^$$-$$10 N

5.8 $$\times$$ 10^$$-$$10 N

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