Physics - Properties of Matter

Question - 1

A cabel of length l can support a maximum load of 1000 kg.  If it is reduced to one-fourth (i.e., 1/4 l), the maximum load it can now support without exceeding the elastic limit would be

  • A 1000 kg
  • B 4000 kg
  • C 250 kg
  • D insufficient data

Question - 2

DImensional formula for modulus of elasticity is

  • A \(MLT^{-2}\)
  • B \(MLT^{2}T^{-1}\)
  • C \(ML^{-1}T^{-2}\)
  • D \(ML^{2}T^{-2}\)

Question - 3

A bolloon floating in air is given a slight lateral horizontal displacement.  The baloon shall now be

  • A in stable equilibrium
  • B in unstable equilibrium
  • C in neutral equilibrium
  • D oscillating

Question - 4

Young's modulus is defined as ratio of normal stress to longitudinal strain.  Hence the term 'force' refers to 

  • A external applied force
  • B deforming force
  • C restoring force
  • D breaking force

Question - 5

Two steel wires have their lengths and diameters in the ratio of 1 : 2.  Their elongation for the same stretching force will be in the ratio

  • A 1 : 4
  • B 4 : 1
  • C 1 : 2
  • D 2 : 1

Question - 6

The length of a wire is increased by 1 mm on the application of a certain load.  In a wire of the same material of twice the length and half the radius of the first, the same force will produce an extension

  • A 1 m
  • B 2 m
  • C 4 mm
  • D 8 mm

Question - 7

Two rods A and B of the same material have both lengths and diameters in the ratio 2:1 respectively. They are subjected to equal torsional couples.  If \(\tau _{B}\) are modulus of torsion

  • A 1 : 4
  • B 8 : 1
  • C 1 : 8
  • D 1 : 1

Question - 8

The magnitude of stress required to increase the length by 100% of a wire of young's modulus Y is

  • A Y
  • B Y/2
  • C Y2
  • D None of these

Question - 9

A vertical wire 2.0 m long and 2.0 \(\times\) \(10^{-6}m^{2}\) in cross-section is found to stretch 0.003 m under a load of 40 N at its lower end.  Assuming Hooke's law holds, the molecular potential energy in J of the streched wire is

  • A 0.024
  • B 0.048
  • C 0.060
  • D 0.6

Question - 10

Choose correct statement :

  • A Metals have high young modulus and low elastic strain
  • B Glass has young modulus and low elastic strain
  • C Plastics are less stiff and do not obey Hooke's law like metals do
  • D All of the above
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