Home
Class 12
PHYSICS
About 5% of the power of a 100 W light b...

About 5% of the power of a 100 W light bulb is converted to visible radiation. What is the average intensity of visible radiation
(a) at a distance of 1m from the bulb?
(b) at a distance of 10 m?
Assume that the radiation is emitted isotropically and neglect reflection.

Text Solution

Verified by Experts

(a) `0.4 W//m^(2)`,
(b) `0.004 W//m^(2)`
Doubtnut Promotions Banner Mobile Dark
|

Topper's Solved these Questions

  • ELECTROMAGNETIC WAVES

    NCERT GUJARATI|Exercise EXERCISES|10 Videos

  • ELECTROMAGNETIC INDUCTION

    NCERT GUJARATI|Exercise ADDITIONAL EXERCISES|7 Videos

  • ELECTROSTATIC POTENTIAL AND CAPACITANCE

    NCERT GUJARATI|Exercise EXERCISES|35 Videos

Similar Questions

Explore conceptually related problems

About 5% of the power of a 100 W light bulb is converted to visible radiation. What is the average intensity of visible radiation : at a distance of 1m from the bulb ?

About 5% of the power of a 100 W light bulb is converted to visible radiation. What is the average intensity of visible radiation : at a distance of 10 m ? Assume that the radiation is emitted isotropically and neglect reflection.

Knowledge Check

  • Photocell is kept at distance of 1 m from the source and incident radiation .Now distance from source is changed to 2m,then….

    A
    no. of photoelectron emitted are `(1)/(4)` times intital value.
    B
    energy of electron emitted is `(1)/(4)` times intitial energy
    C
    no. of electron emitted is half of intital electron emitted.
    D
    Energy of electron emitted is half of initial energy

  • A bus is moving with a speed of 10m/s on a straight road. A scooterist wishes to overtake the bus in 100 s. If the bus is at a distance of 1 km from the scooterist with what speed should the scooterist chase the bus?

    A
    `40 ms ^(-1)`
    B
    `25ms^(-1)`
    C
    `10 ms ^(-1)`
    D
    `20 ms ^(-1)`

  • The electric field intensity produced by the radiations coming from 100W bulb at a 3m distance is E. The electric field intensity produced by the radiations coming from 50W bulb at the same distance is…….

    A
    `E/2`
    B
    2E
    C
    `E/sqrt2`
    D
    `sqrt2 E`

    • Similar Questions

    Explore conceptually related problems

    10 % of the total energy of a 100 W bulb is converted into visible light. Calculate the average intensity out a spherical surface which is at a distance of 1m from the bulb, consider the bulb to be a point source and let the medium be isotropic.

    3% of energy of 100 W bulb is converted into visible light. Find the average intensity on a spherical surface 1 m away from the bulb consider the bulb is point source and medium is isotropic.

    Calculate the electric and magnetic fields produced by the radiation coming from a 100 W bulb at a distance of 3 m. Assume that the efficiency of the bulb is 2.5% and it is a point source.

    Calculate the electric and magnetic fields produced by the radiation coming from a 100 W bulb at a distance of 3 m. Assume that the efficiency of the bulb is 2.5% and it is a point source.

    A bulb of 100 W electrical power emits visible light with 3% efficiency. Find amplitude of oscillations of electric field at 5 m from the bulb.

    Home
    Profile