$\text{v}_\text{A}>\text{v}_\text{B}>\text{v}_\text{C}$
$\text{v}_\text{B}=\frac{1}{2}(\text{v}_\text{A}+\text{v}_\text{C})$
Explanation:
Since the speed of light is a universal constant,
$\text{v}_\text{A}=\text{v}_\text{B}=\text{v}_\text{C}=3\times 10^8\text{m/s}$
$\text{v}_\text{B}=\frac{1}{2}(\text{u}_\text{A}+\text{u}_\text{C})$ This expression also implies that vA = vB = vC
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The heating coils rating at 220 volt and producing 50 cal/sec heat are available with the resistances 55Ω,110 Ω, 220 Ω and 440 Ω. The heater of maximum power will be of
|
(a) 440 Ω |
(b) 220 Ω |
(c) 110 Ω |
(d) 55 Ω |
If half-life of a substance is 3.8 days and its quantity is 10.38 gm. Then substance quantity remaining left after 19 days will be
|
(a) 0.151 gm |
(b) 0.32 gm |
(c) 1.51 gm |
(d) 0.16 gm |
The wavelength of the energy emitted when electron come from fourth orbit to second orbit in hydrogen is 20.397 cm. The wavelength of energy for the same transition in 
is
|
(a) |
(b) |
(c) |
(d) |
In a semiconductor the separation between conduction band and valence band is of the order of
|
(a) 100 eV |
(b) 10 eV |
(c) 1eV |
(d) 0 eV |
What kV potential is to be applied on X-ray tube so that minimum wavelength of emitted X-rays may be 1Å (h = 6.625 
J-sec)
|
(a) 12.42 kV |
(b) 12.84 kV |
(c) 11.98 kV |
(d) 10.78 kV |
A ray is reflected in turn by three plain mirrors mutually at right angles to each other. The angle between the incident and the reflected rays is
| (a) 90° | (b) 60° | (c) 180° | (d) None of these |
Which of the following statement is true
|
(a) Velocity of light is constant in all media |
|
(b) Velocity of light in vacuum is maximum
|
|
(c) Velocity of light is same in all reference frames |
|
(d) Laws of nature have identical form in all reference frames |
