Q. No.A parallel beam of light of intensity \(I_0\) is incident on a lens and the intensity of the emerging beam is \(4I_0\) after it has traversed a further distance of \(30\) cm from the lens. The focal length of the lens is:
1. \(40\) cm
2. \(20\) cm
3. \(45\) cm
4. \(60\) cm
To unlock all the explanations of this course, you need to be enrolled.
To unlock all the explanations of this course, you need to be enrolled.
| 1. | remains unchanged |
| 2. | is displaced along \(+y\) by \((\mu-1)Af\) |
| 3. | is displaced along \(-y\) by \((\mu-1)Af\) |
| 4. | is displaced along \(+x\) by \((\mu-1)Af\) |
To unlock all the explanations of this course, you need to be enrolled.
To unlock all the explanations of this course, you need to be enrolled.
1. down by \(1~\text{cm}\)
2. down by \(2~\text{cm}\)
3. up by \(1~\text{cm}\)
4. up by \(2~\text{cm}\)
To unlock all the explanations of this course, you need to be enrolled.
To unlock all the explanations of this course, you need to be enrolled.
1. \(15^\circ\)
2. \(45^\circ\)
3. \(75^\circ\)
4. \(105^\circ\)
To unlock all the explanations of this course, you need to be enrolled.
To unlock all the explanations of this course, you need to be enrolled.
1. \(1.5\)
2. \(1.75\)
3. \(2.0\)
4. \(2.5\)
To unlock all the explanations of this course, you need to be enrolled.
To unlock all the explanations of this course, you need to be enrolled.
| 1. | \((\mu-1)t\) | 2. | \(2(\mu-1)t\) |
| 3. | \(\mu t\) | 4. | \(2\mu t\) |
To unlock all the explanations of this course, you need to be enrolled.
To unlock all the explanations of this course, you need to be enrolled.
| 1. | \(P_1+P_2\) | 2. | \(|P_1-P_2|\) |
| 3. | \({\Large\frac{P^2_1}{P_2}}\) | 4. | \({\Large\frac{P^2_2}{P_1}}\) |
To unlock all the explanations of this course, you need to be enrolled.
To unlock all the explanations of this course, you need to be enrolled.
| 1. | is parallel but wider. | 2. | is parallel but narrower. |
| 3. | is convergent. | 4. | is divergent. |
To unlock all the explanations of this course, you need to be enrolled.
To unlock all the explanations of this course, you need to be enrolled.
1. \(30^\circ\) downward
2. \(15^\circ\) downward
3. \(30^\circ\) upward
4. \(15^\circ\) upward
To unlock all the explanations of this course, you need to be enrolled.
To unlock all the explanations of this course, you need to be enrolled.
| 1. | \(10\) cm | 2. | \(20\) cm |
| 3. | \(40\) cm | 4. | zero |
To unlock all the explanations of this course, you need to be enrolled.
To unlock all the explanations of this course, you need to be enrolled.
© 2025 GoodEd Technologies Pvt. Ltd.