Different voltages are applied across a P-N junction and the currents are measured for each value. Which of the following graphs is obtained between voltage and current
(a)
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(b)
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(c)
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(d)
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The magnetic field due to a current carrying circular loop of radius 3 cm at a point on the axis at a distance of 4 cm from the centre is 54 mT. What will be its value at the centre of the loop
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(a) 250 m T |
(b) 150 m T |
(c) 125 m T |
(d) 75 m T |
A radio isotope has a half life of 75 years. The fraction of the atoms of this material that would decay in 150 years will be
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(a) 66.6% |
(b) 85.5% |
(c) 62.5% |
(d) 75% |
A moving coil galvanometer of resistance 100 is used as an ammeter using a resistance 0.1 The maximum deflection current in the galvanometer is 100A. Find the minimum current in the circuit so that the ammeter shows maximum deflection
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(a) 100.1 mA |
(b) 1000.1 mA |
(c) 10.01 mA |
(d) 1.01 mA |
Four lowest energy levels of H-atom are shown in the figure. The number of possible emission lines would be
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(a) 3 |
(b) 4 |
(c) 5 |
(d) 6 |
Assertion : Isobars are the element having same mass number but different atomic number.
Reason : Neutrons and protons are present inside nucleus.
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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. |
The core of a transformer is laminated to reduce energy losses due to
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(a) Eddy currents |
(b) Hysteresis |
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(c) Resistance in winding |
(d) None of these |
An electron having charge ‘e’ and mass ‘m’ is moving in a uniform electric field E. Its acceleration will be
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(a) |
(b) |
(c) |
(d) |
