- AArsenic
- BPhosphorus
- ✓Boron
- DBismuth
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The focal length of lens of refractive index 1.5 in air is 30 cm. When it is immersed in a liquid of refractive index , then its focal length in liquid will be
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(a) 30 cm |
(b) 60 cm |
(c) 120 cm |
(d) 240 cm |
Image formed on the retina is
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(a) Real and inverted |
(b) Virtual and erect |
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(c) Real and erect |
(d) Virtual and inverted |
The junction diode in the following circuit requires a minimum current of 1 mA to be above the knee point (0.7 V) of its I-V characteristic curve. The voltage across the diode is independent of current above the knee point. If VB = 5V, then the maximum value of R so that the voltage is above the knee point, will be
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(a) 4.3 kW |
(b) 860 kW |
(c) 4.3 W |
(d) 860 W |
A capacitor with air as the dielectric is charged to a potential of 100 volts. If the space between the plates is now filled with a dielectric of dielectric constant 10, the potential difference between the plates will be
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(a) 1000 volts |
(b) 100 volts |
(c) 10 volts |
(d) Zero |
Assertion : The colour of the green flower seen through red glass appears to be dark.
Reason : Red glass transmits only red light.
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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. |