Home
Class 12
PHYSICS
A comb run through one's dry hair attra...

A comb run through one's dry hair attracts small bits of paper. Why? What happens if the hair is wet or if it is a rainy day? (Remember a paper does not conduct electricity.)

Text Solution

Verified by Experts

This is because the comb gets charged by friction. The molecules in the paper gets polarised by the charged comb, resulting in a net force of attraction. If the hair is wet, or if it is rainy day. Friction between hair and the comb reduces. The comb does not get charged and thus it will not attract small bits of paper.
Promotional Banner

Topper's Solved these Questions

  • ELECTROSTATIC POTENTIAL AND CAPACITANCE

    VIKRAM PUBLICATION ( ANDHRA PUBLICATION)|Exercise Important Questions|3 Videos

  • ELECTROSTATIC POTENTIAL AND CAPACITANCE

    VIKRAM PUBLICATION ( ANDHRA PUBLICATION)|Exercise SAQs|4 Videos

  • ELECTROSTATIC POTENTIAL AND CAPACITANCE

    VIKRAM PUBLICATION ( ANDHRA PUBLICATION)|Exercise Additional Excercise|36 Videos

  • ELECTROMAGNETIC WAVE

    VIKRAM PUBLICATION ( ANDHRA PUBLICATION)|Exercise ADDITIONAL EXERCISES|19 Videos

  • MAGNETISM AND MATTER

    VIKRAM PUBLICATION ( ANDHRA PUBLICATION)|Exercise Additional Exercises|19 Videos

Similar Questions

Explore conceptually related problems

(a) A comb run through one’s dry hair attracts small bits of paper. Why? What happens if the hair is wet or if it is a rainy day? (Remember, a paper does not conduct electricity.) (b) Ordinary rubber is an insulator. But special rubber tyres of aircraft are made slightly conducting. Why is this necessary? (c) Vehicles carrying inflammable materials usually have metallic ropes touching the ground during motion. Why? (d) A bird perches on a bare high power line, and nothing happens to the bird. A man standing on the ground touches the same line and gets a fatal shock. Why?

Answer carefully: (a) Two large conducting spheres carrying charges Q_(1) and Q_(2) are brought close to each other. Is the magnitude of electrostatic force between them exactly given by Q_(1),Q_(2)//4pi epsilon_(0)r^(2) , where r is the distance between their centres? (b) If Coulomb’s law involved 1//r^(3) dependence (instead of would Gauss’s law be still true ? (c) A small test charge is released at rest at a point in an electrostatic field configuration. Will it travel along the field line passing through that point? (d) What is the work done by the field of a nucleus in a complete circular orbit of the electron? What if the orbit is elliptical? (e) We know that electric field is discontinuous across the surface of a charged conductor. Is electric potential also discontinuous there? (f) What meaning would you give to the capacitance of a single conductor? (g) Guess a possible reason why water has a much greater dielectric constant (= 80) than say, mica (= 6).

The discharging current in the atmosphere due to the small conductivity of air is known to be 1800 A on an average over the globe . Why then does the atmosphere not discharge it self completely in due course and becomed electrically neutral ? In other words, what keeps the atmosphere charged?