Question

In: Physics

1. If you apply the potential difference V to a parallel plate capacitor, it is charged...

1. If you apply the potential difference V to a parallel plate capacitor, it is charged to the charge value Q. Now you double the separation between the plates keeping the same V. As a result, charge on the plates will be equal to:

A. 2Q;

B. 4Q;

C. Q;

D. Q/2;

E. Q/4;

2. You have several capacitors of different capacitances. Which statement is correct?

A. If the capacitors connected to a battery in series, charges on all capacitors are the same, but potential differences are different;

B. If the capacitors connected to a battery in series, charges on all capacitors are different, but potential differences are the same;

C. If the capacitors connected to a battery in parallel, charges on all capacitors are different, but potential differences are the same;

D. If the capacitors connected to a battery in parallel, charges on all capacitors are the same, but potential differences are different;

E. A and C;

F. B and D.

3. If you apply voltage V to a long aluminum wire, the power P is dissipated in the wire. If you apply the same voltage V to another aluminum wire which has the same diameter, but is 2 times longer, the dissipated power will be equal to:

A. 4P;

B. 2P;

C. P;

D. P/2;

E. P/4.

Expert Solution

1. Correct Answer: D. Q/2, Capacitance is inversely proportional to the separation between the plates. If you double the separation between the plates the capacitance becomes half. Further, as the voltage is constant the charge on the plates is proportional to the capacitance. Hence charge becomes half.

2. Correct Answer: E. A and C, In the series connection of different capacitors, charge on each capacitor is the same. Voltage on each capacitor is inversely proportional to the capacitance. In a parallel connection of different capacities, voltage is the same because along parallel parts voltage is always the same. Further, charge on each capacitor is proportional to the capacitance.

3. Correct Answer:D. P/2 , For a given voltage, power consumed is inversely proportional to the resistance of the wire. If the length of the wire becomes double, its resistance also doubles. Hence the power consumed will become half.

genius_generous answered 2 years ago

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