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In a Hall probe, electrons passing through the semiconductor experience a force due to a magnetic field.

Explain why a potential difference is created across the semiconductor as a result of the application of the magnetic field.

Thanks in advance.

A beam of protons and π+ mesons moving at the same speed is directed into a uniform magnetic field in the same direction as the field. 

a) Explain why the beam is not deflected by the field.

b) If the particles had been directed into the field in a direction at right angles to the field lines at the same speed, state and explain what effect this would have had on the beam.

Thanks in advance.

The Earth's magnetic field at a certain position on the Earth's surface has a horizontal component of 18 micro T due North and a downwards vertical component of 55 micro T. Calculate the magnitude of the Earth's magnetic field at this position. Can someone explain why the answer is 58micro T. Thanks in advance.

I was trying to backup a folder (which contains photos and photoshop files) from my desktop to usb and cancelled the transfer by accident but the folder just disappeared afterwards. I tried to paste the content in a new folder but it says the files no longer located in desktop and says to verify the item's location. Is there anyway to recover the files??

My hp printer would not function when I have a third party black and white ink catridge and a genuine hp colour ink catridge together. How do I solve this problem??

Assume that extension is proportional to the tension.

A wire of natural length 50cm, diameter 1.5mm and Young's modulus 3.2GPa is stretched to a new length of 52.4cm, which is below the limit of proportionality. How much work was done in order for this to happen?

A weight lifter pulls a 2000kg car forwards at an average speed of 1.5ms^-1 against a force of 1250N. What is his average power output? 

A cricket batsman hits a ball at a speed of 27ms^−1 at an angle of 60 degrees to the horizontal. How far away would you have to stand in order to catch it (assuming you want to catch it just before it hits the ground)? 

Assume the downward acceleration is 9.8 ms^-2.

You are trying to drop essential survival supplies from an aeroplane to help the survivors of a crash who are stranded. You are flying 300m above them, and your aircraft can travel no slower than 30ms^-1. You fly on a straight line which will pass over the survivors. 

How far (in metres) in advance of overflying the survivors do you need to drop the package? Assume that the downward acceleration is 9.8 ms^-2.

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