- 1(current)
Q. No.The following diagram shows light travelling from \(A\) to \(B\) after bouncing off a plane mirror at \(P.\) The time taken is \(t_{APB} .\) If, however, light were to take a different path, \(AQB\) (shown by the dotted line), the time taken is \(t_{AQB}.\)
Then,
Then,
| 1. | \(t_{APB}=t_{AQB}\) |
| 2. | \(t_{APB}<t_{AQB}\) |
| 3. | \(t_{APB}>t_{AQB}\) |
| 4. | \(t_{APB}\) may be greater than or less than \(t_{AQB}\) depending on whether \(Q\) is to the left or right of \(P.\) |
Subtopic: Â Reflection at Plane Surface |
Level 4: Below 35%
Hints
Assume that the corner of \(O\) of the room is the origin, and the axes \(x,y,z \) are along the edges. The three walls meeting orthogonally at \(O\) are perfect mirrors. A ray of light travelling parallel to the vector \(-(\hat i+2\hat j+\hat k) \) is incident on the \(y\text-z\) mirror (wall). The emerging ray, after all reflections, will be along:
1. \(\hat i-2\hat j-\hat k\)
2. \(\hat i+\hat k-2\hat j\)
3. \(-\hat i+2\hat j+\hat k\)
4. \(\hat i+2\hat j+\hat k\)
1. \(\hat i-2\hat j-\hat k\)
2. \(\hat i+\hat k-2\hat j\)
3. \(-\hat i+2\hat j+\hat k\)
4. \(\hat i+2\hat j+\hat k\)
Subtopic: Â Reflection at Plane Surface |
Level 3: 35%-60%
Hints
\(AB\) and \(BC\) are a pair of mirrors inclined so that the angle between their planes is \(60^{\circ}\), as shown in the figure. A ray of light \(XY\) is incident on \(AB\) and emerges as the ray \(ZW\) after two reflections. If the incident ray is rotated so that \(\angle AYX\) decreases by \(15^{\circ}\), then \(\angle WZC\):
| 1. | increases by \(15^{\circ}\). | 2. | increases by \(30^{\circ}\). |
| 3. | decreases by \(15^{\circ}\). | 4. | decreases by \(30^{\circ}\). |
Subtopic: Â Reflection at Plane Surface |
 52%
Level 3: 35%-60%
Hints
- 1(current)
Q. No.
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