- A1.6 × 10-19
- B4.8 × 10-19
- C1.6 × 10-10
- D10
Explanation:
1 electron volt is the amount of work done if an electron is passed through a potential difference of 1V. Therefore the work done = 1V × charge of an electron = 1.602 × 10-19 J. But it is a small quantity and hence we use kilo electron volt and mega electron volt in practical.
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Which of the following theories is the most satisfactory about the origin of the universe
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(a) Big Bang theory |
(b) Pulsating theory |
(c) Steady state theory |
(d) None of these |
A proton of mass m and charge +e is moving in a circular orbit in a magnetic field with energy 1 MeV. What should be the energy of α - particle (mass = 4m and charge = + 2e), so that it can revolve in the path of same radius
|
(a) 1 MeV |
(b) 4 MeV |
(c) 2 MeV |
(d) 0.5 MeV |
X-rays are
| (a) Stream of electrons |
| (b) Stream of positively charged particles |
| (c) Electromagnetic radiations of high frequency |
| (d) Stream of uncharged particles |
20 μA current flows for 30 seconds in a wire, transfer of charge will be
|
(a) 2 |
(b) 4 |
(c) 6 |
(d) 8 |
A convex lens forms a real image of a point object placed on its principal axis. If the upper half of the lens is painted black:
Assertion : Current is passed through a metallic wire, heating it red. When cold water is poured on half of its portion, then rest of the half portion become more hot.
Reason : Resistances decreases due to decrease in temperature and so current through wire increases.
|
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
|
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
|
(c) If assertion is true but reason is false. |
|
(d) If the assertion and reason both are false. |
PQRS is a square loop made of uniform conducting wire the current enters the loop at P and leaves at S. Then the magnetic field will be
|
(a) Maximum at the centre of the loop |
(b) Zero at the centre of loop |
|
(c) Zero at all points inside the loop |
(d) Zero at all points outside of the loop |