Electrical Circuits

The resistance of an IDEAL ammeter is assumed to be

• zero

• 0.1Ω

• 1 to 2Ω

• infinite

Which of the following formulae (in which the symbols have their usual meanings) is a mathematical expression of Ohm's Law?

• V = IR

• P = VI

• Q = It

• E = Pt

Which of the following statements for the parallel circuit in the diagram is/are true?

I. The potential difference across each of the resistors is the

same

II. The potential difference between X and Y is the same as

that across the 2Ω resistor

III. The current through each of the resistors is different.

• I only

• III only

• I and III only

• I, II and III

Which of the following circuit symbols represents a fuse?

• 
• 
• 
• 

Which of the following statements about insulators is/are true?

I. In an insulator all electrons are bound firmly to their atoms

II. In an insulator many electrons can move freely from atom to atom

III. An insulator cannot be charged by rubbing

IV. A good insulator retains the charge better than a conductor

• I only

• I and II only

• II and III only

• II and IV

The current in a wire is one ampere if a charge of

• 10C flows through it in 10s

• 1C flows through it in 1s

• 10C flows through it in 1s

• 100C flows through it in 10s

In the parallel circuit shown, ALL of the current, I, supplied by the battery

• goes through each of the resistors

• goes through the largest resistor only

• goes through the smallest resistor only

• equals the sum of the currents in the two resistors

Which of the following relationships gives a correct value for the combined resistance  $R_T$   of resistors  $R_1$ ,  $R_2$  and  $R_3$  connected in parallel?

•  $R_T\ =\ R_1\ +R_2\ +\ R_3$  

• 
  

   $R_T\ =\frac{R_1R_2R_3}{R_1+R_2+R_3}$  

•  $R_T\ =\frac{1}{R_1}+\frac{1}{R_2}+\frac{1}{R_3}$  

•  $\frac{1}{R_T}\ =\frac{1}{R_1}+\frac{1}{R_2}+\frac{1}{R_3}$  

Which of the following relationships between electrical quantities is correct?

• V =PI

• R = VI

• $Q\ =\ \frac{E}{V}$

• E = VI

Which of the following is NOT a measure of energy?

• Power x time

• Current x pd

• Pd x charge

• Force x distance