Electrostatic Potential and Capacitance — Physics STD 12 Science — Question

The speed of light depends:

Assertion  :   The presence of water molecules makes separation of ions easier in electrolyte.  

Reason    : The presence of water molecules in electrolyte decreases the resistance of electrolyte.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If the assertion and reason both are false.

The work-function of a metal is:

The half life period of a radioactive element X is same as the mean life time of another radioactive element Y. Initially both of them have the same number of atoms. Then

(a) X and Y have the same decay rate initially

(b) X and Y decay at the same rate always

(c) Y will decay at a faster rate than X

(d) X will decay at a faster rate than Y

Two point charges of the same polarities are hung with the help of two threads and kept close. The angle between the threads will be _________ if the system is taken to space.

The half-life period and the mean life period of a radioactive element are denoted respectively by T_h and T_m Then?

Three capacitors each of 6μF  are available. The minimum and maximum capacitances which may be obtained are

(a) 6 μF, 18 μF

(b) 3 μF, 12 μF

(c) 2 μF, 12 μF

(d) 2 μF, 18 μF

Two positive point charges of 12 μC  and 8 μC  are 10cm apart. The work done in bringing them 4 cm closer is

(a) 5.8 J

(b) 5.8 eV

(c) 13 J

(d) 13 eV