An air filled parallel plate capacitor has capacity C. If distance between plates is doubled and it is immersed in a liquid then capacity becomes twice. Dielectric constant of the liquid is
|
(a) 1 |
(b) 2 |
(c) 3 |
(d) 4 |
(d) 4
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On increasing the number of electrons striking the anode of an X-ray tube, which one of the following parameters of the resulting X-rays would increase
| (a) Penetration power | (b) Frequency | (c) Wavelength | (d) Intensity |
Assertion : The ferromagnetic substance do not obey Curie’s law.
Reason : At Curie point a ferromagnetic substance start behaving as a paramagnetic substance.
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
An electric kettle has two heating coils. When one coil is used, water in the kettle boils in 5 minutes, while when second coil is used, same water boils in 10 minutes. If the two coils, connected in parallel are used simultaneously, the same water will boil in time
|
(a) 3 min 20 sec |
(b) 5 min |
(c) 7 min 30 sec |
(d) 2 min 30 sec |
The direction of ray of light incident on a concave mirror is shown by PQ while directions in which the ray would travel after reflection is shown by four rays marked 1, 2, 3 and 4 (Fig). Which of the four rays correctly shows the direction of reflected ray?
The expression for thermo e.m.f. in a thermocouple is given by the relation E = 40 θ - 
, where θ is the temperature difference of two junctions. For this, the neutral temperature will be
|
(a) 100℃ |
(b) 200℃ |
(c) 300℃ |
(d) 400℃ |