1) Give one example of a substance whose resistance lowers with an increase in temperature.
A semiconductor is the best example.
2) How is a conductor’s resistance affected by an increase in temperature?
A conductor’s resistance increases when the temperature rises.
3) How is an ammeter connected to an electric circuit?
An ammeter is usually joined in series in the electric circuit.
4) What is the main procedure to convert a galvanometer into an ammeter?
A galvanometer is typically converted into an ammeter by linking a suitable low resistance wire (shunt) in parallel orientation with it.
5) How are voltmeters attached to an electric circuit?
Voltmeters are always connected in parallel.
6) What is the main procedure to convert a galvanometer into a voltmeter?
A galvanometer is typically converted into a voltmeter by linking a high resistance in series orientation with it.
7) What is a potentiometer?
A potentiometer is an electrical apparatus used for precise calculation of minute potential differences and to analyse the e.m.f.s of the available primary cells.
8) What is the principle of a potentiometer?
The principle of a potentiometer is stated as the potential dropped along a section of a wire of uniform area carrying a stable electric current is directly proportional to the wire’s length.
9) What is meant by a cell’s e.m.f?
It is the highest possible potential difference along with a cell’s terminals in an open electric circuit.
10) What is meant by a potential gradient?
The potential gradient is the potential variation per unit length of the given potentiometer wire.
11) Why is a potentiometer preferred over a voltmeter for the calculation of e.m.f?
For the purpose of measuring e.m.f accurately, no electric current should be taken from the cell. In the case of a potentiometer, the readings are noted when the electric current is zero. So the potentiometer measures the e.m.f correctly.
12) What is meant by terminal voltage?
Terminal voltage is the potential difference along with a cell’s terminals when the electric current is being taken from it.
13) Is a voltmeter used for measuring the e.m.f.?
No, the voltmeter takes electric current from the cell.
14) What is the reason behind the null point?
The null point is acquired because the cell’s e.m.f. is balanced by the potential variation along a particular length of the connected potentiometer wire.
15) What is meant by a cell’s internal resistance?
The resistance applied by the cell’s electrolyte is known as the cell’s internal resistance.
16) What is meant by a primary cell?
A primary cell is a type of cell which cannot be recharged.
17) What is meant by a secondary cell?
A secondary cell is a type of cell which can be recharged.
18) Why does a secondary cell give more electric current than a primary cell of the identical e.m.f.?
A secondary cell gives more electric current than a primary cell because a secondary cell possesses a very low internal resistance.
19) Which type of cells (primary cells or secondary cells) is employed in automobiles?
Secondary cells are typically used in automobiles because they provide the needed large beginning current due to this cell’s relatively low internal resistance.
20) Is sensitivity impacted by potential gradients?
Yes, the lesser the potential gradients, the higher will be the sensitivity.
21) How is the potentiometer’s sensitivityaffected by the length of the wire?
The sensitivity of the potentiometer rises with the increase in the wire’s length.
22) On what constraints does the cell’s internal resistance depend?
In the case of a cell, internal resistance depends on:
- nature of the electrolyte
- the concentration of the electrolyte
- nature of the electrodes
- distance between the plates
- temperature
- area of the plates inside the electrolyte
22) Can a potentiometer be used to calculate the secondary cell’s internal resistance?
No, a secondary cell possesses very little internal resistance. Due to the low value, it has no considerable effect on the potential difference.
23) What will result if the cross-section area of the potentiometer wire is non-uniform?
The potential difference across the wire will not be proportional to its length.
24) What can be the reason for one-sided deflection in galvanometers?
(a) The primary cell’s e.m.f. may surpass that of the main circuit cell.
(b) Circuit connections may be incorrect or loose.
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