- A$\alpha$ -particle
- B$\beta$ -particle
- C$\gamma$ -particle
- DDeuterium nucleus
Explanation:
$^4_2$He→$^4_2$He+2+2e−
$^4_2$He+2 is alpha particle. Because it has charge equal to +2e and mass is four times the mass of one proton.
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A cell of emf 6 V and resistance 0.5 ohm is short circuited. The current in the cell is
|
(a) 3 amp |
(b) 12 amp |
(c) 24 amp |
(d) 6 amp |
A transformer with efficiency 80% works at 4 kW and 100 V. If the secondary voltage is 200 V, then the primary and secondary currents are respectively
|
(a) 40 A, 16 A |
(b) 16 A, 40 A |
(c) 20 A, 40 A |
(d) 40 A, 20 A |
The sensitiveness of a moving coil galvanometer can be increased by decreasing
|
(a) The number of turns in the coil |
|
(b) The area of the coil |
|
(c) The magnetic field |
|
(d) The couple per unit twist of the suspension |
In Millikan's experiment for the determination of the charge on the electron, the reason for using the oil is
|
(a) It is a lubricant |
(b) Its density is higher |
|
(c) It vapourises easily |
(d) It does not vapourise |