An electrical cable is made up of one thick strand of copper wire that is surrounded by eight thin strands of copper wire. All nine strands of wire are connected in parallel with each other. A cross-section of the cable is shown. [Figure 32.1] Each thin strand of wire has cross-sectional area A and length L. The thick strand of wire has cross-sectional area 4A and length L. The cable has total resistance R. Which expression gives the resistivity of copper?

Charge carriers, each of charge q, move along a wire of fixed length. The number density of the charge carriers in th…

The electric current in a wire may be calculated using the equation I = Anvq. Which statement is not correct?

A wire of cross-sectional area 5.0 × 10⁻⁶ m² is made of a metal of resistivity 50 × 10⁻⁸ Ω m. The potential differenc…

When ice melts, it contracts. Which row is correct for ice turning into water?

Atmospheric pressure at sea level has a value of 100 kPa. The density of sea water is 1020 kg m⁻³. At what depth in t…

Electromagnetic waves from an unknown source in space were found to be significantly diffracted when passing through …