Current electricity questions | form three Physics

If one cell in a perfect three-cell torch is placed in the opposite direction, then switching on the torch will:
A. give normal light
B. give bright light
C. give dim light
D. not give light

a) State Ohm’s Law.
b) A 12 volt battery is connected across a resistor of 15 ohms.
(i) Draw an electrical circuit showing the stated components and the direction of flow of current.
(ii) Calculate the moment of current flowing.

The force that drives an electric current through an electric component is called
A Coulomb B Farad C Ampere
D Potential difference E An e.m.f.

Which device is used to control the flow of current in one direction within an electronic circuit?

When a galvanometer is used to measure electric current in a circuit it must be connected with a
A shunt in series B multiplier in parallel
C shunt in parallel D multiplier in series
E Shunt and multiplier in parallel

(a) With the aid of a diagram, explain the function of a fuse in an electrical appliance.
(b) A circuit in a house is protected by a 10 A fuse. The circuit is connected to the 240 V mains.The following appliances are connected to the circuit:

Determine whether the fuse will blow on or off if all appliances are turned on.

By drawing circuit diagrams supported by graphs, compare the charging and discharging processes of a capacitor given that you are provided with a cell (E), a voltmeter (V), a switch (S), a capacitor (C), a resistor (R) and connecting wires.

Two wires A and B of the same material and length have the cross-sectional area in the ratio 2:1. If the same potential difference is applied accross each wire, comment on the amount of current flowing between the wires A and B.

Why a low voltage supply should have a low internal resistance. Explain by using an appropriate formula.