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A lamp has a rating of 18V 9W. How much energy is transferred to the bulb in 5 minutes? Calculate the current through it when connected to a 18V supply.

The first question comes from the realisation that the power rating, "9W" represents 9 joules being supplied every second and so can be written as 9J/s and so in 5 minutes (o...

AN
Answered by Alexander N. Physics tutor
4010 Views

Resistors of 5 ohms and 10 ohms are connected in series with a battery supplying 3 volts. What is the total resistance ? And calculate the current in the circuit.

For the first part of the question we note that the resistors are in series, this means we can simply add together the resistance, giving a value of:
15 ohms

For the second part we ...

AN
Answered by Alexander N. Physics tutor
18635 Views

On a see-saw Mary, weight 600N balances John, weight 200N when she sits 1.5m away from the pivot. How far from the pivot is John?

Using the knowledge that the moments are balanced, we can create an equation to calculate the distance John is from the pivot:

600N1.50m = 200N(distance)
(600/200)*1.5 = di...

AN
Answered by Alexander N. Physics tutor
11434 Views

The loudspeaker produces a sound wave with a frequency of 850 hertz and a wavelength of 0.4 metres. Calculate the speed of this sound wave. Give the unit

The speed of a wave is given by "Frequency*Wavelength=Wave speed". Hence, the speed is 340. With the units of speed being m/s

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Answered by Alexander N. Physics tutor
9635 Views

Describe the photoelectric effect and what it tells us about the properties of light .

The photoelectric effect describes the process by which surface electrons are emitted from a metal when light is shined on it. This occurs because the electrons are able to absorb the electromagnetic e...

LC
Answered by Lorenzo C. Physics tutor
14168 Views

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