Search SchoolNGR

Saturday, 15 August 2026
Register . Login

Physics Past Questions and Answers

Topic: The thermos flask

Jamb Physics Questions - The thermos flask

Question 1:
Which of the following statements is correct? Silvered walls of a vacuum flask are used to prevent
  • A Heat loss due to conduction
  • B Vacuum loss
  • C Heat entry into the inner flask due to convection
  • D Heat loss due to radiation
  • E Heat loss due to convection
View Answer & Explanation
Question 2:
The vacuum in a thermos flask helps to reduce heat transfer by?
  • A Convection and radiation
  • B Convection and conduction
  • C Conduction and radiation
  • D Radiation only
View Answer & Explanation
Question 3:
The space between the double glass walls of a thermos flask is evacuated space are silvered. The residual source of heat loss takes place by
  • A Convection
  • B Radiation from the surface
  • C Conduction through the stopper and the glass
  • D Conduction across the walls
View Answer & Explanation
Question 4:
The main reason for making the cover of a vacuum flask airtight is to prevent heat loss by
  • A Convection
  • B Conduction
  • C Radiation
  • D Evaporation
View Answer & Explanation
Question 5:
When cold water is poured on a can containing hot water, the can collapses because the
  • A Steam condeses and occupies the partial vacuum in the can
  • B External air pressure counter balances the pressure within the can
  • C Steam expands to occupy the vacuum remaining in the can
  • D External pressure becomes greater than the pressure within the can.
View Answer & Explanation