The minimum wavelength of X-rays produced by electrons accelerated by a potential difference of volts is equal to
(a) 
|
(b) 
|
(c) 
|
(d) 
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What fraction of a radioactive material will get disintegrated in a period of two half-lives
|
(a) Whole |
(b) Half |
(c) One-fourth |
(d) Three-fourth |
$\lambda'>\lambda$
$\lambda'=\lambda$
$\lambda'<\lambda$
An electron makes a transition from orbit n = 4 to the orbit n = 2 of a hydrogen atom. The wave number of the emitted radiations (R = Rydberg's constant) will be
|
(a) |
(b) |
(c) |
(d) |
A capacitor of capacitance 6μF is charged upto 100 volt. The energy stored in the capacitor is
|
(a) 0.6 Joule |
(b) 0.06 Joule |
(c) 0.03 Joule |
(d) 0.3 Joule |
A heater coil connected to a supply of a 220 V is dissipating some power 
The coil is cut into half and the two halves are connected in parallel. The heater now dissipates a power 
The ratio of power 
is
|
(a) 2 : 1 |
(b) 1 : 2 |
(c) 1 : 4 |
(d) 4 : 1
|
A photodetector is made from a semiconductor In 0.53Ga 0.47As with Eg = 0.73 eV. What is the maximum wavelength, which it can detect
|
(a) 1000 nm |
(b) 1703 nm |
(c) 500 nm |
(d) 173 nm |
