A man is looking at a small object placed at his near point. Without altering the position of his eye or the object, he puts a simple microscope of magnifying power 5X before his eyes. The angular magnification achieved is:
- A5
- B2.5
- C1
- D0.2
A man is looking at a small object placed at his near point. Without altering the position of his eye or the object, he puts a simple microscope of magnifying power 5X before his eyes. The angular magnification achieved is:
We have,
h = Object height
u = Object distance = 25cm
D = Near point = 25cm
Now,
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A single slit of width a is illuminated by violet light of wavelength 400 nm and the width of the diffraction pattern is measured as y. When half of the slit width is covered and illuminated by yellow light of wavelength 600 nm, the width of the diffraction pattern is
|
(a) The pattern vanishes and the width is zero |
(b) y / 3 |
|
(c) 3y |
(d) None of these |
The energy gap of silicon is 1.14 eV. The maximum wavelength at which silicon will begin absorbing energy is
|
(a) 10888 Å |
(b) 1088.8 Å |
(c) 108.88 Å |
(d) 10.888 Å |
In the circuit of a triode valve, there is no change in the plate current, when the plate potential is increased from 200 volt to 220 volt and the grid potential is decreased from – 0.5 volt to –1.3 volt. The amplification factor of this valve is
|
(a) 15 |
(b) 20 |
(c) 25 |
(d) 35 |
The capacity of a condenser in which a dielectric of dielectric constant 5 has been used, is C. If the dielectric is replaced by another with dielectric constant 20, the capacity will become
|
(a) |
(b) 4C |
(c) |
(d) 2C |
A radioactive substance has a half-life of 1 year. The fraction of this material, that would remain after 5 years will be
|
(a) |
(b) |
(c) |
(d) |
An electron passing through a potential difference of 4.9 V collides with a mercury atom and transfers it to the first excited state. What is the wavelength of a photon corresponding to the transition of the mercury atom to its normal state
|
(a) 2050 Å |
(b) 2240 Å |
(c) 2525 Å |
(d) 2935 Å |
In an hydrogen atom, the electron revolves around the nucleus in an orbit of radius 0.53
. Then the electrical potential produced by the nucleus at the position of the electron is
|
(a) – 13.6 V |
(b) – 27.2 V |
(c) 27.2 V |
(d) 13.6 V |