Tiêu đề 19. Heating and Chemical Effects of current Medium.pdf ✅

1. The approximate value of heat produced in 5 min. by a bulb of 210 watt is (J = 4.2 joule/calorie) (a) 15,000 (b) 1,050 (c) 63,000 (d) 80,000 2. Two wires ‘A’ and ‘B’ of the same material have their lengths in the ratio 1 : 2 and radii in the ratio 2 : 1. The two wires are connected in parallel across a battery. The ratio of the heat produced in ‘A’ to the heat produced in ‘B’ for the same time is (a) 1 : 2 (b) 2 : 1 (c) 1 : 8 (d) 8 : 1 3. A heating coil is labelled 100 W, 220 V. The coil is cut in half and the two pieces are joined in parallel to the same source. The energy now liberated per second is (a) 200 J (b) 400 J (c) 25 J (d) 50 J