| 1. | \(3000~\text{m}\) | 2. | \(2800~\text{m}\) |
| 3. | \(2000~\text{m}\) | 4. | \(1000~\text{m}\) |
| 1. | negative | 2. | zero |
| 3. | positive | 4. | infinity |
| 1. | along the axis of rotation |
| 2. | along the radius, away from the centre |
| 3. | along the radius towards the centre |
| 4. | along the tangent to its position |
| 1. | along south-west | 2. | along eastward |
| 3. | along northward | 4. | along north-east |
| 1. | \(\mathrm{Na}\) only | 2. | \(\mathrm{Cs}\) only |
| 3. | both \(\mathrm{Na}\) and \(\mathrm{K}\) | 4. | \(\mathrm{K}\) only |
| 1. | the electric field inside the surface is necessarily uniform. |
| 2. | the number of flux lines entering the surface must be equal to the number of flux lines leaving it. |
| 3. | the magnitude of electric field on the surface is constant. |
| 4. | all the charges must necessarily be inside the surface. |