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Explain, in terms of pressure, how straws draw water into your mouth.

Atmospheric pressure is an expression for the force exerted on a surface (in this case the water surface) per unit area caused by air particle collisions on the surface. In a cup of water, there is a uniform...
BS
Answered by Benjamin S. • Physics tutor
14309 Views

Why can heat only be transferred through a vacuum by radiation, and not conduction or convection? (3)

Heat transfer by conduction and convection works by particles colliding and transferring energy, as there are no particles in a vacuum heat transfer can only occur by radiation. This is because radiation inv...
JW
Answered by James W. • Physics tutor
43543 Views

State one property that all EM waves have in common.

All EM waves travel at the same speed in a vacuum.
EH
Answered by Elizabeth H. • Physics tutor
3017 Views

A cup of boiling water (100 degrees C) (0.2kg) transfers 20 000J of heat to its surrounding in 1 hour. What temperature is the water in the kettle after 1 hour?

To answer this we need to use the equation Q = MC(T1-T2) We want to know what T2 is (ie the temperature after one hour). So rearrange the equation to get T2 = T1 - Q/MC No substitute the values given: T2 = 1...
CJ
Answered by Callum J. • Physics tutor
4169 Views

Why is it that spectral lines emitted from stars in distant galaxies appear to be shifted towards the red end of the electromagnetic spectrum?

Spectral lines are caused by electrons within atoms being excited up energies levels by absorbing specific frequencies of light (this produces absorption lines- dark lines in an otherwise continuous spectrum...
LC
Answered by Louise C. • Physics tutor
6545 Views