Maximum voltage transfer occurs when the load matches the plate (internal) resistance.

The control grid (or intensity grid) of a CRT adjusts the beam current and thus the brightness of the spot on the screen.

An electricity meter measures the energy consumed (usually in kilowatt-hours).

Lagging power factor (inductive) is corrected by adding capacitance (a condenser) in parallel to provide leading current.

For an ideal capacitor in sinusoidal steady state, current leads voltage by 90°, independent of frequency.

Total r =20×0.1=2 Ω. For discharged emf 20×1.8=36 V: R=(80−36)/10 −2=4.4−2=2.4 Ω; for charged emf 52 V: R=(80−52)/10 −2=2.8−2=0.8 Ω, so range 2.4 to 0.8 Ω, option B.

To measure true EMF, the measurement must be made with no external current drawn so internal drops are absent, hence B.

A filament lamp's resistance changes with temperature as it heats, so it does not obey Ohm's law (which assumes constant resistance).

A JFET is a voltage-controlled device: its gate-to-source voltage controls the drain current, so the input excitation is a voltage signal.

Dividing into n parts gives each resistance R/n and n in parallel gives equivalent R/n², so power ∝1/R_eq = n² times the original, i.e., n² H.