Advertisements
Advertisements
Question
If the potential difference between the ends of a fixed resistor is halved, the electric power will become:
Options
double
half
four times
one-fourth
Solution
one-fourth
Since P = ` V^2/R`, when the potential difference is halved, the power becomes one-fourth
APPEARS IN
RELATED QUESTIONS
State the relation between potential difference, work done and charge moved.
If a potential difference of 10 V causes a current of 2 A to flow for 1 minute, how much energy is transferred?
The p.d. across a lamp is 12 V. How many joules of electrical energy are changed into heat and light when: a current of 2 A flows through it for 10 s?
Ohm's law state a relation between potential difference and ___________.
Why do electricians wear rubber hand gloves while working with electricity?
Find the resistance of a conductor if the electric current flowing through it is 0.35 A when the potential difference across it is 1.4 V.
A cell of e.m.f 2.0 V and internal resistance 1Ω is connected to the resistors of 3Ω and 6Ω in series. Calculate:
(i) the current drawn from the cell,
(ii) the p.d. across each resistor,
(iii) the terminal voltage of the cell and
(iv) the voltage drop.
A current of 0.2 A flows through a conducting wire for 5 minutes. How much charge will flow?
A current of 100 mA. flows through a wire. The charge on an electron is 1.6 × 10-19 C. Find the number of electrons passing per second through the cross-section of the conductor.
Find out the following in the electric circuit given in Figure
- Effective resistance of two 8 Ω resistors in the combination
- Current flowing through 4 Ω resistor
- Potential difference across 4 Ω resistance
- Power dissipated in 4 Ω resistor
- Difference in ammeter readings, if any.
