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A bulb is made using two filaments.A swi...

A bulb is made using two filaments.A switch selects whether the filaments are used individually or in parallel. When used with a 15V battery, the bulb can be operated at 5W ,10W and 15W. What should be the resistances of the filaments ?

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The various resistances of the bulbs = ` v^2/p`
` Resistance are `
` ((15)^2/5), (15^2/10), (15^2/15) = 45 , 22 , 5 , 15. `
Since two resistances when used in
parallel have resistances less than both.
The resistances are 45 & 22.5 .
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HC VERMA-ELECTRIC CURRENT IN CONDUCTORS-Exercises
  1. Three bulbs,each having a resistance of 180(Omega)are connected in par...

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  2. Suppose you have three resistor of (20 Omega),(50Omega)and (100 Omega)...

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  3. A bulb is made using two filaments.A switch selects whether the filame...

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  4. if a current of 12mA exists in the 5k(Omega) resistor, find the curre...

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  5. An ideal battery sends a current of 5A in a resistor.When another resi...

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  6. Find the equivalent resistances of the network shown in figurebetween ...

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  7. A wire of resistance 15.0(Omega)is bent to form a regular hexagon ABCD...

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  8. Consider the circuit shown in figure.Find the current through the10(Om...

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  9. Find the currents through the three resistors shown in Figure

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  10. Shown a part of an electric circuit, The potentials at the points a,b,...

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  11. Each of the resistors shown in figure has a resistances of 10(Omega)an...

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  12. Find the potential difference V(a)-V(b)in the circutis shown in figure

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  13. In the circuit shown in figure ,(epsilon)(1)=3V,(epsilon)(2)=2V,(epsil...

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  14. Find the current through the 10(Omega)resistor shown in figure.

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  15. Find the current in the resistor shown in figure.

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  16. What should be the value of R in figure fo which the current in it is ...

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  17. Find the equivalent resistance of the circuit shown in figure between ...

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  18. Find the current measured by the ammeter in the circuit shown in figur...

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  19. Consider the circuit shown in figure.Find (a) the current in the circu...

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  20. Twelve wire, each having equal resistance r, are joined to form a cube...

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