- AFerromagnetic materials.
- BParamagnetic materials.
- CDiamagnetic materials.
- DAll of the above.
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Two insulated metallic spheres of 3 μF and 5 μF capacitances are charged to 300 V and 500V respectively. The energy loss, when they are connected by a wire is
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(a) 0.012 J |
(b) 0.0218 J |
(c) 0.0375 J |
(d) 3.75 J |
Assertion : A potentiometer of longer length is used for accurate measurement.
Reason : The potential gradient for a potentiometer of longer length with a given source of e.m.f. becomes small.
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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. |
How should people wearing spectacles work with a microscope?
The image formed by a concave mirror:
If
millimho, then on increasing plate voltage by 50 V, how much the grid voltage is changed so that plate current remains the same
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(a) – 2.86 V |
(b) – 4 V |
(c) + 4 V |
(d) + 2 V |
The n rows each containing m cells in series are joined in parallel. Maximum current is taken from this combination across an external resistance of 3W resistance. If the total number of cells used are 24 and internal resistance of each cell is 0.5 W then
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(a) m = 8, n = 3 |
(b) m = 6, n = 4 |
(c) m= 12, n = 2 |
(d) m = 2, n = 12 |
Which of the following statements are true regarding Bohr's model of hydrogen atom
(I) Orbiting speed of electron decreases as it shifts to discrete orbits away from the nucleus
(II) Radii of allowed orbits of electron are proportional to the principal quantum number
(III) Frequency with which electrons orbits around the nucleus in discrete orbits is inversely proportional to the principal quantum number
(IV) Binding force with which the electron is bound to the nucleus increases as it shifts to outer orbits Select correct answer using the codes given below
Codes :
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(a) I and III |
(b) II and IV |
(c) I, II and III |
(d) II, III and IV |