Question 1
A battery has an emf,  , and internal resistance, r. The battery is connected to a variable resistor, R, as shown below. | |
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| a) | As the variable resistor is varied, the power dissipated in it will also vary. Show that the power, P, dissipated in the variable resistor is given by |
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| b) | If = 9V and r = 3W, what is the maximum value of the power dissipated in the variable resistor, R? |
| An electron of charge, e, and mass, m, enters the uniform electric field between two parallel charged plates, as shown in the diagram below. |
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| The p.d. across the plates is V and the distance between them is d. The initial velocity of the electron is of magnitude, u and is parallel to the plates. The point of entry into the field is midway between the two plates. The electron hits the lower plate after having moved a distance x in the field (x measured parallel to the plates). Show that |
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