16.A 20 ohm resistance with an unknown resistance R in series is connected to the potentiometer arrangement having a constant current in its main circuit. If p. d. across 2 ohm resistance is balanced at 300 cm length and p. d. across R at 360 cm length, then R is

17.A galvanometer of resistance 98 ohm is shunted by a resistance of 2 ohm. The fraction of total current that passes through the galvanometer is

18.Two identical resistors are connected in parallel, then in series. The effective resistances are in the ratio

19.A bettery of e.m. f. E and in internal resistance r is being used and is supplying current i in the circuit. The terminal potential will be

20.A voltmeter reading up to 1000 m V is calibrated with a potentiometer. An e. m. f. of 2.08 V is balanced across 8.4 m of the wire. The balancing length is 3.68 m when the voltmeter reads 0.9 V. The error in the voltmeter reading is