Dual Nature of Radiation and Matter — Physics STD 12 Science — Question

Consider the motion of the tip of the minute hand of a clock. In one hour:

1. The displacement is zero.
2. The distance covered is zero.
3. The average speed is zero.
4. The average velocity is zero.

If a conductor has a potential V ≠ 0 and there are no charges anywhere else outside, then:

Which state of triply ionised Baryllium (  has the same orbital radius as that of the ground state of hydrogen

(a) n = 4

(b) n = 3

(c) n = 2

(d) n = 1

A non.monochromatic light is used in an experiment on photoelectric effect. The stopping potential:

A 4μF conductor is charged to 400 volts and then its plates are joined through a resistance of 1kΩ. The heat produced in the resistance is

(a) 0.16 J

(b) 1.28 J

(c) 0.64 J

(d) 0.32 J

Assertion :   In all conductors, for studying the thermoelectric behaviour or metals, lead is taken as a reference metal.  

Reason    : In lead, the Thomson effect is negative.

(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.

Assuming that the dimmest visible star to the naked eye has a magnitude of about 6. Brightness of planet Venus (magnitude = – 4) w.r.t. this star is

(a) 10,000 times brighter	(b) 2000 times brighter
(c) 15000 times brighter	(d) 4000 times brighter

In the circuit here, the steady state voltage across capacitor C is a fraction of the battery e.m.f. The fraction is decided by

(a) R1 only

(b) R1 and R2 only

(c)  and   only

(d)  and

When the speed of electrons increase, then the value of its specific charge?