The direction of force on a current-carrying conductor in a magnetic field is given by MCQ with Answer and Explanation

Explanation:
Femto (f) = 10⁻¹⁵. Pico (p) = 10⁻¹², nano (n) = 10⁻⁹, atto (a) = 10⁻¹⁸. The prefix chain: milli 10⁻³, micro 10⁻⁶, nano 10⁻⁹, pico 10⁻¹², femto 10⁻¹⁵, atto 10⁻¹⁸. Mnemonic: Femto is 'fifteen'.

Explanation:
Manometer measures pressure difference. Barometer atmospheric pressure.

Explanation:
Thomas Alva Edison invented the practical incandescent light bulb in 1879. He also invented phonograph. Tesla contributed to AC system. Faraday electromagnetic induction. Bell telephone.