Advertisements
Advertisements
प्रश्न
Which of the following terms does not represent electrical power in a circuit?
पर्याय
I2R
IR2
VI
`"V"^2/"R"`
Advertisements
उत्तर
IR2
Explanation:
Electrical power is given by the expression P = VI ....(i)
According to Ohm’s law,
V = IR
Substituting the value of V in (i), we get
P = (IR) × I
P = I2R
Similar, to Ohm’s law,
I = `"V"/"R"`
Substituting the value of I in (i), we get
P = `"V" xx "V"/"R" = "V"^2/"R"`
From this, it is clear that the equation IR2 does not represent electrical power in a circuit.
संबंधित प्रश्न
If a bulb of 60W is connected across a source of 220V, find the current drawn by it.
What is the SI unit of (i) electric energy, and (ii) electric power?
What is the maximum power in kilowatts of the appliance that can be connected safely to a 13 A ; 230 V mains socket?
When an electric lamp is connected to 12 V battery, it draws a current of 0.5 A. The power of the lamp is:
(a) 0.5 W
(b) 6 W
(c) 12 W
(d) 24 W
An electric bulb marked 220 V, 100 W will get fused if it is made to consume 150 W or more. What voltage fluctuation will the bulb withstand?
What is the current I in the given circuit (Fig. )?
Fig . shows the essent ial features of a battery operated bell. The hammer strikes the gong when the swi tch is closed . State and explain the effect of using the following material successively to form the core.
(a) Plastic
(b) Steel
(c) Copper
Mention three uses of the carbon arc.
Two lamps are rated 220V, 50W and the other rated 220V, 100W are connected in series with the mains of 220 V. Explain, why the 50W lamp glows more?
State relative advantages and disadvantages of ring system of wiring over the tree system.
Three 250 W heaters are connected in parallel to a 100 V supply, Calculate the energy supply in kWh to the three heaters in 5 hour.
With reference to the diagram shown below calculate:
(i) The equivalent resistance between P and Q.
(ii) The reading of ammeter.
(iii) The electrical power between P and Q.
How can electric energy consumed by an electric appliance be calculated in kilowatt hour (kWh)?
A family uses a light bulb of 100W, a fan of 100W, and a heater of 1000W, each for 8 hours a day. If the cost of electricity is Rs. 2 per unit, what is the expenditure to the family per day, on electricity?
Find the cost of operating an electric toaster for two hours if it draws 8 A current on a 110 volt circuit. The cost of electrical energy is Rs. 2.50 per kWh.
The electrical power and current in the circuit relates by ______
A room has AC run for 5 hours a day at a voltage of 220V. The wiring of the room consists of Cu of 1 mm radius and a length of 10 m. Power consumption per day is 10 commercial units. What fraction of it goes in the joule heating in wires? What would happen if the wiring is made of aluminium of the same dimensions?
`[ρ_(Cu) = 1.7 xx 10_(Ωm)^-8, ρ_(Al) = 2.7 xx 10^-8 Ωm]`
A conductor of 10 Ω is connected across a 6 V ideal source. The power supplied by the source to the conductor is ______.
1 kWh = ______ J.
