Question

a) State the Si unit of current and define it.
(b) An electric circuit is to be set-up for studying the relationship between the potential difference maintained between the points 'X' and 'Y', and the current flowing through the wire XY. This circuit will consist of a niriwome wire XY, an ammeter, a voltmeter, four cells of 1.5 V each and a plug key.
(i) Draw its circuit.
(ii) The graph shown in the figure was plotted between V and I What would be the value of V and I corresponding to the points A and C on the graph ? Analyse these values and draw the conclusion.


CBSE Class X Science LA (5 Marks)

Answer 1

Answer:

si unit of current is ampere

Answer 2

a) The SI unit of current is ampere. Ampere is defined as the flow of 1 coulomb of charge in a time interval of 1 second.

Explanation for b part:

• For the XY nichrome wire, 4 cells are connected in series to get maximum emf output. If they are connected in parallel then the emf will  be equal to 1.5 volts as all the cells have an emf of only 1.5volts.
• The ammeter is connected in series as it has 0 resistance, we get same current flowing through XY and ammeter A without changing its value
• The voltmeter is connected in parallel to the nichrome wire XY to measure the voltage output accross XY.
• since the voltmeter has very large resistance, connecting it in series will create a different voltage drop accross XY and thus cuurent and voltage alters. therefore Voltmeter is connected in parallel to the XY nichrome wire.