In X-ray tube when the accelerating voltage V is halved, the difference between the wavelength of Ka line and minimum wavelength of continuous X-ray spectrum
|
(a) Remains constant |
(b) Becomes more than two times |
|
(c) Becomes half |
(d) Becomes less than two times |
(d) Becomes less than two times
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The ratio of thickness of plates of two transparent mediums A and B is 6 : 4. If light takes equal time in passing through them, then refractive index of B with respect to A will be
|
(a) 1.4 |
(b) 1.5 |
(c) 1.75 |
(d) 1.33 |
The correct curve between the magnetic induction (B) along the axis of a long solenoid due to current flow i in it and distance x from one end is
|
(a)
|
(b)
|
(c)
|
(d)
|
The resistance of a wire is 
per metre. It is bend in the form of a circle of diameter 2 m. A wire of the same material is connected across its diameter. The total resistance across its diameter AB will be
|
(a) |
(b) |
(c) 0.88 |
(d) 14π |
A galvanometer with a resistance of 12 W gives full scale deflection when a current of 3 mA is passed. It is required to convert it into a voltmeter which can read up to 18 V. the resistance to be connected is
|
(a) 6000 W |
(b) 5988 W |
(c) 5000 W |
(d) 4988 W |
A thermo couple is formed by two metals X and Y metal X comes earlier to Y in Seebeck series. If temperature of hot junction increases beyond the temperature of inversion. Then direction of current in thermocouple will so
|
(a) X to Y through cold junction |
(b) X to Y through hot junction |
|
(c) Y to X through cold junction |
(d) Both (b) and (c) |
If the radioactive decay constant of radium is 1.07 
per year, then its half life period is approximately equal to
|
(a) 8,900 years |
(b) 7,000 years |
(c) 6,476 years |
(d) 2,520 years |
Heavy water is
|
(a) Water at 4 ℃ |
|
(b) Compound of deuterium and oxygen |
|
(c) Compound of heavy oxygen and heavy hydrogen |
| (d) Water, in which soap does not lather |
