Physics MCQs for Class 9 with Answers
Glass and transparent polythene sheets allow radiations of wavelength to pass through them:
Long
Medium
Short
All
Leslie’s cube is filled with:
Cold water
Hot water
Mercury
Air
The process in which heat is transmitted form one body to another by the interaction of atoms and the movement of free electrons is known as
convection
radiation
conduction
both (a) and (b)
During recent years the percentage of __________ increased considerably on earth:
Carbon dioxide
Nitrogen
Oxygen
Methane
Which of the following is a good radiator of heat?
A shining slivered surface
A dull black surface
A white surface
A green coloured surfaced
The mathematical formula of thermal conductivity is
k =Q/t x L/A (T1 – T2)
k =Q/t x L/A (T1 + T2)
k =t/Q x L/A (T1 – T2)
k =2Q/t x L/A (T1 + T2)
Metals are good conductor of heat due to
Free Electrons
Big size of their molecules
Small size of their molecules
Rapid vibrations of their atoms
Which surface is best reflector of heat?
dull black surface
coloured surface
white surface
shining slivered surface
In thermo flask radiation is stopped by using :
Green color
Transparent
Silver color
Nil
Glider pilots use __________ movement of hot air currents due to convection of heat:
Downward
Upward
Left
right
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