Atoms — Physics STD 12 Science — Question

A direct current of 4 A is flowing through any circuit. Root mean square value of the current is:

An inductor of reactance 1Ω and a resistor of 2Ω are connected in series to the terminals of a 6V (rms) a.c. source. The power dissipated in the circuit is:

The materials which allow to pass electricity through them easily are called as:

The nucleus   after two successive   decays will give

(a)

(b)

(c)

(d)

The charge on proton is:

An ionized gas contains both positive and negative ions. If it is subjected simultaneously to an electric field along the +x direction and a magnetic field along the +z direction, then

(a) Positive ions deflect towards +y direction and negative ions towards –y direction

(b) All ions deflect towards +y direction

(c) All ions deflect towards –y direction

(d) Positive ions deflect towards –y direction and negative ions towards +y direction

The charge on a capacitor of capacitance 10 μF connected as shown in the figure is         

(a) 20 μC

(b) 15 μC

(c) 10 μC

(d) Zero

A potentiometer having the potential gradient of 2 mV/cm is used to measure the difference of potential across a resistance of 10 ohm. If a length of 50 cm of the potentiometer wire is required to get the null point, the current passing through the 10 ohm resistor is (in mA)

(a) 1

(b) 2

(c) 5

(d) 10

A capacitor of capacitance C is charged to a potential V. The flux of the electric field through a closed surface enclosing the capacitor is: