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Laws Of Motion

Question
CBSEENPH11026252
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An electric bulb has a rated power of 50 W at 100 V. If it is used on an AC source 200 V, 50 Hz, a choke has to be used in series with it. This choke should have an inductance of

  • 0.1 mH

  • 1 mH

  • 0.1 mH

  • 1.1 H

Solution

D.

1.1 H

Power P = I × V

             = V R × V

           P = V2 R

Resistance of bulb

          R = V2P

           R = 100250

               = 200 Ω 

Current through bulb

            (I) = VR

                 = 100200

              I  =  0.5 A

In a circuit containing inductive reactance (XL ) and resistance (R ), impedance (Z) of the circuit is

             Z = R2 + ω2 L2              ...... (i)

             Z = 2000.5

             Z = 400 Ω

Now,      XL2 = Z2 - R2

             XL2  = ( 400 )2  - ( 200 )2

           2 πf L2 = 12 × 104

             L = 23 × 1002π × 50

                  = 23 π

              L = 1.1 H

Some More Questions From Laws of Motion Chapter

State Galileo’s law of motion.

Define inertia.

When the branches of an apple tree are shaken, the apples fall down. Why?

A person jumping out from a moving car or bus falls forward. Why?

Due to what type of inertia, the spark leaves the grind stone tangentially while sharpening the knife?

Which law of motion is also called law of inertia?

What is measure of inertia of body?

Which law of motion defines the force?

What happens to a stone tied to the end of string and whirled in a circle if the string suddenly breaks?

Which law of motion gives the quantitative knowledge of force?

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