Q35 of 35 Page 94

Find out the following in the electric circuit given in Figure 12.9

(a) Effective resistance of two 8 Ω resistors in the combination

(b) Current flowing through 4 Ω resistor

(c) Potential difference across 4 Ω resistance

(d) Power dissipated in 4 Ω resistor

(e) Difference in ammeter readings, if any.

(i) since resistances are connected in parallel


Therefore, effective resistance 1/R’ = 1/8+1/8 = 1/4


R’ = 4Ω


(ii) Current can be calculated with the help of Ohm’s law:


I = V/R = 8/4 = 2 A


(iii)Potential difference is given by, V= IR


V= 4 × 2 =8 Watt


(iv)Reading in ammeter A1, I = V/R = 8/4 = 2 A


Reading in ammeter A2 = 8/4


= 2 A


Difference in ammeter readings = 2- 2= 0

More from this chapter

All 35 →
31

What is electrical resistivity of a material? What is its unit? Describe an experiment to study the factors on which the resistance of conducting wire depends.

 32

How will you infer with the help of an experiment that the same current flows through every part of the circuit containing three resistances in series connected to a battery?

 33

How will you conclude that the same potential difference (voltage) exists across three resistors connected in a parallel arrangement to a battery?

 34

What is Joule’s heating effect? How can it be demonstrated experimentally? List its four applications in daily life.