A. 4

B. 6

C. 8

D. 12

One junction of thermo couple is at 0^{0}C and the other junction is heated .Maximum current in the thermo couple is observed when hot junction is at 240^{0}C.The temperature of the hot junction at which the direction of current reverses is

A cell of emf 2V and negligible resistance is connected in series with a resistance of 5 ohm,and a potentiometer wire of resistance 10 ohm.what is the potential drop per cm if the length of the potentiometer wire is 10m.The emf of a cell which is balanced by 750cm long wire is

A galvanometer of resistance 100Ω gives full scale deflection with 5mA current.To convert it into a 5 volt range voltmeter,the value of resistance connected in series is

Four bulbs each marked 40 W. 250 V are connected in series with 250 V source. The total power output is

An electrical meter of internal resistance 20Ω gives full scale deflection when one milliampere current flows through it.The maximum current that can be measured by using three resistors of resistance 12Ω each,in milliamperes is