Nichrome is an alloy of nickel, chromium, manganese ad iron having a resistivity of about 60 times more than that of copper. It is used for making the heating elements of electrical heating appliances.
Explain the following.
Why is the tungsten used almost exclusively for filament of electric lamps?
Answer
The melting point and of Tungsten is an alloy which has very high melting point and very high resistivity so does not burn easily at a high temperature.
A simple circuit consists of a resistor, a battery, and connecting wires. How must an ammeter be connected in a circuit to correctly read the current?
Answer
The ammeter must be connected in the series to read the current correctly. Ammeter has very low resistance If it is connected in parallel across any load then all current in circuit will
choose lower resistive path (i.e ammeter) which will cause the circuit to be damaged. Hence it is used in series. Also the current in the series is always same.
Draw a schematic diagram of an electric circuit consisting of a battery of two cells each of $\text{1.5 V, 5 } \Omega, \text{10 } \Omega \text{ and 15 } \Omega$ resistors and a plug key, all connected in series.