An electric current passes through a long straight wire. At a distance 5cm from the wire, the magnetic field is B. The field at 20cm from the wire would be:

Neutral temperature of a thermo couple is 250⁰C.If the value of’a’ is 15μv/⁰C,the value of ‘b’ is

The lengths of two wires made of same material are 2m and 1m. Their radii are 1mm and 2mm. The ratio of their specific resistances is

When an unknown resistance and a resistance of 4 ? are connected in the left and right gaps of a meterbridge, The balance point is obtained at 50 cm. The shift in the balance point if a 4 ? resistance is now connected in parallel to the resistance in the right gap is

Two unknown resistance X and Y are connected to left and right gaps of a meter bridge and the balancing point is obtained at 80 cm from left. When a 10Ω resistance is connected in parallel to X, the balance point is 50 cm from left. The values of X and Y respectively are

A current is passed through two coils connected in series. The potential difference across the first coil is 3 volts and that of the second coil 4.5 volts. If the first coil has resistance of 2 ohm, the resistance of the second coil is:

A 4Ω resistor in series with 8Ωresistance are connected to 12 V supply.If another resistor of 8Ω is connected across the 8Ω resistor the current drawn from source would be

A maximum current 0.5mA can be passed through a galvanometer of resistance 20Ω.The resistance to be connected in series to convert it into voltmeter of range 0-5V is

The cold junction of a thermocouple is at 0⁰ C,The thermo e.m.f produced in the thermocouple is given by the equation E=16T-0.04T²V , where T is the temperature of the hot junction.The temperature of inversion and neutral temperature of the thermo couple are

Thermo emf produce per 1⁰C temperature difference between the junction is 0.005V.when cold junction is at 10⁰C,and hot junction is at t⁰C,thermo emf produced is 0.5 V.,The value of t is