Explanation:
An electron will absorb energy when jumping from the 1st orbit to the 3rd orbit.
Only by absorbing energy, an electron will be able to jump from the first orbit to the third orbit in the atomic spectrum.
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The magnetic field at the centre of a circular coil of radius r is π times that due to a long straight wire at a distance r from it, for equal currents. Figure here shows three cases : in all cases the circular part has radius r and straight ones are infinitely long. For same current the B field at the centre P in cases 1, 2, 3 have the ratio
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(a) |
(b) |
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(c) - |
(d) |
A Young's double slit experiment uses a monochromatic source. The shape of the interference fringes formed on a screen is
|
(a) Straight line |
(b) Parabola |
(c) Hyperbola |
(d) Circle |
A symmetric double convex lens is cut in two equal parts by a plane perpendicular to the principal axis. If the power of the original lens was 4D, the power of a cutlens will be:
An X-ray has a wavelength of 0.010 Å. Its momentum is
| (a) 2.126 × 10–23 kg-m/sec | (b) 6.626 × 10-22 kg-m/sec |
| (c) 3.456 × 20–25 kg-m/sec | (d) 3.313 × 10–22 kg-m/sec |
A magnet of magnetic moment 2
is aligned in the direction of magnetic field of 0.1 T. What is the net work done to bring the magnet normal to the magnetic field
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(a) 0.1 J |
(b) 0.2 J |
(c) 1 J |
(d) 2 J |
Assertion : If the distance between parallel plates of a capacitor is halved and dielectric constant is made three times, then the capacitor becomes 6 times.
Reason : Capacity of the capacitor does not depend upon the nature of the material.
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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. |
