Advertisements
Advertisements
Question
An electrical bulb is marked 200V, 100W. Calculate the electrical resistance of its filament. If five such
bulbs are connected in series to a 200V supply, how much current will flow through them?
Advertisements
Solution
Voltage V = 200 V, Power P = 100 W
∴ Electrical current = `P/V = 100/200 = 1/2` Amp
∴ Electrical resistance `R = V/I = 200/("I/2") `= 400 Ω
if five bulbs are connected in series to 200V
∴ Total resistance RT = 400 + 400 + 400 + 400 + 400 = 2000Ω
Current flowing thorugh a bulb `I = 200/2000 = 0.1 A `
APPEARS IN
RELATED QUESTIONS
If the potential difference across the ends of a conductor is 220 V and the resistance of the conductor is 44 Ω (ohm), then the current flowing through is _________.
- 0.2 A
- 0.5 A
- 2 A
- 5 A
Graph showing the variation of current versus voltage for a material Ga As is shown in the figure. Identify the region of
(i) negative resistance
(ii) where Ohm's law is obeyed.
Keeping the p.d. constant, the resistance of a circuit is halved. The current will become:
(a) one-fourth
(b) four time
(c) half
(d) double
Consider the sacle of voltmeter shown in the diagram and answer the following questions :
(a) What is the least count of the voltmeter?
(b) What is the reading shown by the voltmeter ?
(c) If the voltmeter is connected across a resistor of 20 `Omega` how much current is flowing through the resistor?
Define the following:
Coulomb
What is meant by the drift speed of free electrons?
State the relation correlating the electric current flowing in a conductor and the voltage applied across it. Also, draw a graph to show this relationship.
The slope of voltage (V) versus current (I) is called:
A student carries out an experiment and plots the V-I graph of three samples of nichrome wire with resistances R1, R2 and R3 respectively. Which of the following is true?
