Q32 / 46 · NTA Abhyas (NEET) 2020 · Physics · Kinetic Theory of Gases

Air is pumped into an automobile tube up to a pressure of 200 kPa in the morning when the air temperature is 22 ℃. During the day, the temperature rises to 42 ℃ and the tube expands by 2%. The pressure of the air in the tube at this temperature will be approximately

  • A
    212 kPa
     
  • Correct answer
    B
    209 kPa
     
  • C
    206 kPa
     
  • D
    200 kPa
     

Solution

The ideal gas law is the equation of state of an ideal gas. The state of an amount of gas is determined by its pressure, volume and temperature. The equation has the form

pV=nRT

where, p is pressure, V the volume, n the number of moles, R the gas constant and T the temperature.

∴   p1V1T1=p2V2T2

Given, p1=200 kPa, V1=V, T1=273+22=295 K, V2=V+0.02 V

T2=273+42=315 K

200×V295=p2×1.02V315

⇒  p2=200×315295×1.02

p2=209 kPa

Hence, the correct answer is option: 'B'.

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