Explanation:
No, thermionic emissions and photoelectric emissions are not the same. During thermionic emissions, the electrons are emitted from the metal surface by providing heat energy, whereas, during photoelectric emission light energy is emitted when electrons are emitted from the surface of the metal. So, it is the opposite in operation.
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Two ions having masses in the ratio 1 : 1 and charges 1 : 2 are projected into uniform magnetic field perpendicular to the field with speeds in the ratio 2 : 3. The ratio of the radii of circular paths along which the two particles move is
|
(a) 4 : 3 |
(b) 2 : 3 |
(c) 3 : 1 |
(d) 1 : 4 |
Two spheres A and B of radius ‘a’ and ‘b’ respectively are at same electric potential. The ratio of the surface charge densities of A and B is
|
(a) |
(b) |
(c) |
(d) |
At noon the sun appears white because:
Two particles X and Y having equal charges, after being accelerated through the same potential difference, enter a region of uniform magnetic field and describes circular path of radius 
and 
respectively. The ratio of mass of X to that of Y is
|
(a) |
(b) |
(c) |
(d) |
Ge and Si diodes conduct at 0.3 V and 0.7 V respectively. In the following figure if Ge diode connection are reversed, the valve of V0 changes by
|
(a) 0.2 V |
(b) 0.4 V |
(c) 0.6 V |
(d) 0.8 V |
