Question
Why does a phonograph-record attract dust particles just after it is cleaned?
✓
Answer
When a phonograph record is cleaned, it develops a charge on its surface due to rubbing. This charge attracts the neutral dust particles due to induction.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
What is the radius of the path of an electron $($mass $9 \times 10^{-31} \ kg$ and charge $1.6 \times 10^{-19} C )$ moving at a speed of $3 \times 10^7 m / s$ in a magnetic field of $6 \times 10^{-4} T$ perpendicular to it? What is its frequency? Calculate its energy in $keV .\left(1 eV =1.6 \times 10^{-19} J \right)$.
→In the Rutherford's nuclear model of the atom, the nucleus (radius about $10^{-15} m$ ) is analogous to the sun about which the electron move in orbit (radius $\approx 10^{-10} m$ ) like the earth orbits around the sun. If the dimensions of the solar system had the same proportions as those of the atom, would the earth be closer to or farther away from the sun than actually it is? The radius of earth's orbit is about $1.5 \times 10^{11} m$. The radius of sun is taken as $7 \times 10^8 m$.
→Derive an expression for drift velocity of free electrons in a conductor in terms of relaxation time.
A circular loop of one turn carries a current of 5.00A. If the magnetic field B at the centre is 0.200mT find the radius of the loop.
A staircase contains three steps each 10cm high and 20cm wide (figure). What should be the minimum horizontal velocity of a ball rolling off the uppermost plane so as to hit directly the lowest plane?
A copper wire of diameter 1.6 mm carries 20A. Find the maximum magnitude of the magnetic field $\overrightarrow{\text{B}}$ due to this current.
→A heavy mass m is hanging from a string in equilibrium without breaking it. When this same mass is set into oscillation, the string breaks. Explain.
While gas from a cooking gas cylinder is used, the pressure does not fall appreciably till the last few minutes. Why?
Write characteristics of electro magnetic waves.
A wire forming a loop is dipped into soap solution and taken out so that a film of soap solution is formed. A loop of $6.28\ cm$ long thread is gently put on the film and the film is pricked with a needle inside the loop. The thread loop takes the shape of a circle. Find the tension in the thread. Surface tension of soap solution $= 0.030\ N/m$.
→