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What are the differences between sound waves and electromagnetic waves?

Propagation: Sound waves are longitudinal , meaning that the vibrations occur parallel to the direction of propagation (travel). Electromagnetic waves are transverse , meaning that the vibrations occur perpe...
WL
Answered by Wendy L. • Physics tutor
77636 Views

Explain the photo-electric effect and describe how the intensity of light effects rate of electron emission.

The photo-electric effect is the way in which electrons are released from the surface of a metal when there is an incident light ray. The particle model of light, as part of wave-particle duality, suggests t...
IW
Answered by Ira W. • Physics tutor
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Calculate the resistance of a uniform wire of diameter 0.5mm, length 2m and resistivity 1.7x10^-8Ωm.

R=ρ L/AR= (1.7*10^-8 2)/(0.0005^2 π/4)R=0.173Ω
HW
Answered by Heather W. • Physics tutor
2839 Views

Explain the input and output energy sources for a car engine. How would you calculate the efficiency? Explain in terms of the inputs and outputs how the efficiency could be improved.

The input is chemical energy (in the form of fuel). The outputs areSound (not useful)Kinetic (useful)Heat (may be useful)The efficieny is given by useful output energy divided by total input (or output) ener...
SH
Answered by Samuel H. • Physics tutor
21267 Views

Sketch a graoh of current against potential difference for a filament lamp and explain its shape.

(draw diagram on whiteboard) As the potential difference increases, the current increases, since V=IR (where V is the potential difference, I is the current and R is the resistance). Initially the current in...
TD
Answered by Tamanna D. • Physics tutor
2920 Views