Question

The following apparatus are available in a laboratory:
Cell: adjustable from 0 to 1.5 V
Resistors : 4ohm and 12 ohm
Ammeters: A1 of range 0 to 3A; Least count 0.1A
A2 of range 0to 1A; Least count 0.05 A
Voltmeters : V1 of range 0 to 10 V ; Least Count 0.5 V
V2 of range 0 to 5 V; Least Count 0.1 V
The best combination of voltmeter and ammeter for finding the equivalent resistance of the
resistors in series would be:
a) ammeter A1 and voltmeter V1 b) ammeter A1 and voltmeter V2
c) ammeter A2 and voltmeter V1 d) ammeter A2 and voltmeter V2
with explanation too

Answer 1

Answer:

Value of Resistors = 4 ohm and 12 ohm

Hence effective resistance in a series connection would be 12 + 4 = 16 ohm.

Coming to the maximum voltage provided by the battery, it is 1.5 V.

Current flowing through the circuit is given as:

→ 1.5 V / 16 ohm = 0.09375 A

Since the value of the current is very small, both ammeters can show the value. But when it comes to precision, the ammeter with a lesser least count would be preferable since it gives the most closer value.

Hence Ammeter A2 should be chosen.

Similarly, the voltage of 1.5 V is shown by both the voltmeters. But again precision plays a crucial role due to which voltmeter with lesser least count is preferred.

Hence V2 should be chosen.

Hence the correct option is (d).