An X-ray machine has an accelerating potential difference of 25,000 volts. By calculation the shortest wavelength will be obtained as (h = 6.63 
; e =
coulomb)
|
(a) 0.25 Å |
(b) 0.50 Å |
(c) 1.00 Å |
(d) 2.50 Å |
(b) 0.50 Å
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The radius of a metallic sphere if its capacitance is 1/9 F, is
|
(a) |
(b) |
(c) |
(d) |
Consider the following statements A to B and identify the correct answer
A. Polarised light can be used to study the helical surface of nucleic acids.
B. Optics axis is a direction and not any particular line in the crystal
|
(a) A and B are correct |
(b) A and B are wrong |
|
(c) A is correct but B is wrong |
(d) A is wrong but B is correct |
Four condensers are joined as shown in the adjoining figure. The capacity of each is 8 μF. The equivalent capacity between the points A and B will be
|
(a) 32 μF |
(b) 2 μF |
(c) 8 μF |
(d) 16 μF |
The magnetic needle of a tangent galvanometer is deflected at an angle 30o due to a magnet. The horizontal component of earth’s magnetic field 0.34 × 10–4 T is along the plane of the coil. The magnetic intensity is
|
(a) 1.96 × 10–4 T |
(b) 1.96 × 10–5 T |
(c) 1.96 × 104 T |
(d) 1.96 × 105 T |
The electric bulbs have tungsten filaments of same length. If one of them gives 60 watt and other 100 watt, then
|
(a) 100 watt bulb has thicker filament |
|
(b) 60 watt bulb has thicker filament |
|
(c) Both filaments are of same thickness |
|
(d) It is possible to get different wattage unless the lengths are different |
The focal length of a convex mirror is 20 cm its radius of curvature will be
|
(a) 10 cm |
(b) 20 cm |
(c) 30 cm |
(d) 40 cm |
In transformer, core is made of soft iron to reduce
|
(a) Hysteresis losses |
(b) Eddy current losses |
|
(c) Force opposing electric current |
(d) None of the above |
$\lambda\geq\lambda_0$
$\lambda\geq2\lambda_0$
$\lambda\leq\lambda_0$
$\lambda<\frac{\lambda_ 0}{2}.$
