Advertisements
Advertisements
Question
The figure shows a circuit. When the circuit is switched on, the ammeter reads 0.5 A.
(i) Calculate the value of the unknown resistor R.
(ii) Calculate the charge passing through the 3 Ω resistor in 120 s.
(iii) Calculate the power dissipated in the 3 Ω resistor.
Advertisements
Solution
(i) We know, V = IR'
⇒ 6 = 0.5 × R'
⇒ R' = 12 Ohm
∵ R' = 3 + R
⇒ 12 = 3 + R
⇒ R = 9 Ohm
(ii) Charge, q = i t
⇒ q = 0.5 × 120 = 60 Coulomb
(iii) Power dissipation, p = i2R
p = 0.52 × 3 = 0.75 Watt
RELATED QUESTIONS
Calculate the quantity of heat produced in a 20 Ω resistor carrying 2.5 A current in 5 minutes.
Which of the following statements correctly defines a volt?
(a) a volt is a joule per ampere.
(b) a volt is a joule per coulomb.
How much energy is transferred by a 12 V Power supply to each coulomb of charge which it moves around a circuit?
Ohm's law state a relation between potential difference and ___________.
What is Ohm's law? Explain how it is used to define the unit of resistance.
Calculate the power used in the 2 Ω resistor in each of the following circuits: a 4 V battery in parallel with 12 Ω and 2 Ω resistors.
Draw a graph of Potential difference (V) versus Current (I) for an ohmic resistor. How can you find the resistance of the resistor from this graph?
Suppose there are three resistors A, B, and C having resistances r1, r2, and r3 respectively. If R represents their equivalent resistance, establish the following relation R = r1 + r2 + r3 when joined in series.
A 10 m long wire of a particular material is of resistance 5Ω What will be the resistance if the wire is doubled itself.
Electric potential is a measure of the ______ on the unit positive charge to bring it to that point against all electrical forces.
