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Write the Formula for Electric Power in Terms of Potential Difference and Current. - Science

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प्रश्न

Write the formula for electric power in terms of potential difference and current.

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उत्तर १

In terms of potential difference and current, electric power is given as:
Electric power, P = potential difference, V x current, I
                      P = VI

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उत्तर २

In terms of potential difference and current, electric power is given as:
Electric power, P = potential difference, V x current, I
                      P = VI

shaalaa.com
  या प्रश्नात किंवा उत्तरात काही त्रुटी आहे का?
पाठ 1: Electricity - Exercise 7

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संबंधित प्रश्‍न

1 kWh = ________ J


At what frequency is AC supplied to residential houses?


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


Which of the following is likely to be the correct wattage for an electric iron used in our homes? 

(a) 60 W
(b) 250 W
(c) 850 W
(d) 2000 W


How much energy does a 100 W electric bulb transfer in 1 minute?

(a) 100 J
(b) 600 J
(c) 3600 J
(d) 6000 J


The table below shows the current in three different electrical appliances when connected to the 240 V mains supply: 

Appliance Current
Kettle 8.5 A
Lamp 0.4 A
toaster 4.8 A
  1. Which appliance has the greatest electrical resistance? How does the data show this?
  2. The lamp is connected to the main supply by using a thin, twin-cored cable consisting of live and natural wires. State two reasons why this cable should not be used for connecting the kettle to the mains supply.
  3. Calculate the power rating of the kettle when it is operated from the 240 V mains supply.
  4. A main takes the kettle abroad where the mains supply is 120 V. What is the current is the kettle when it is operated from the 120 V supply?

Explain why, filament type electric bulbs are not power efficient.


 1Kwh =`( 1  "volt "xx 1 am pere xx.............)/1000`


Two resistors A and B of resistance 4 Ω and 6 Ω respectively are connected in parallel. The combination is connected across a 6 volt battery of negligible resistance. Calculate: (i) the power supplied by the battery, (ii) the power dissipated in each resistor.


An electric kettle is rated 2.5 kW, 250 V. Find the cost of running the kettle for two hours at Rs. 5.40 per unit.


A current passes through a resistor. Let K1 and K2 represent the average kinetic energy of the conduction electrons and the metal ions, respectively.


Define electric power. An electrical device of resistance R is connected across a source of voltage V and draws a current I. Derive an expression for power in terms of current and resistance.


If the rating of an electric bulb is 100W – 230V, Explain its meaning.


An electric bulb is marked 100 W, 230 V. What does this mean?


Give two precautious that you would take while putting off an electric switch.


How is the amount of heat produced calculated due to the passage of current in a metallic conductor? Derive an expression for it.


A bulb is connected to a battery of e.m.f. 6V and internal resistance 2Ω A steady current of 0.5A flows through the bulb. Calculate the heat energy dissipated in the bulb in 10 minutes.


A torch bulb is rated at 3 V and 600 mA. Calculate it’s

  1. power
  2. resistance
  3. energy consumed if it is used for 4 hours.

To minimise the power loss in the transmission cables connecting the power stations to homes and factories, the transmission cables carry current ______.

The unit of e.m.f. of a cell is ____________.


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