Two thin lenses whose powers are +2D and –4D respectively combine, then the power of combination is
|
(a) – 2D |
(b) + 2D |
(c) – 4D |
(d) + 4D |
(a) – 2D
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
What is the current in the circuit shown below
| (a) 0 amp |
(b)  amp
|
(c) 1 amp |
(d) 0.10 amp |
The resistance of the series combination of two resistance is S. When they are joined in parallel the total resistance is P. If S = nP, then the minimum possible value of n is
|
(a) 4 |
(b) 3 |
(c) 2 |
(d) 1 |
A radio isotope has a half life of 75 years. The fraction of the atoms of this material that would decay in 150 years will be
|
(a) 66.6% |
(b) 85.5% |
(c) 62.5% |
(d) 75% |
To get three images of a single object, one should have two plane mirrors at an angle of
|
(a) 30° |
(b) 60° |
(c) 90° |
(d) 150° |
A beam of well collimated cathode rays travelling with a speed of 5 
enter a region of mutually perpendicular electric and magnetic fields and emerge undeviated from this region. If |B| = 0.02T, the magnitude of the electric field is
|
(a) |
(b) 2.5 |
(c) 1.25 |
(d) 2 |
