MCQ
LCD stands for:
- ALight Carrying Diode
- BLiquid Crystal Display
- CLong Crystal Display
- DLight Crystal Display
Explanation:
LCD stands for "Liquid Crystal Display".
LCD is a special thin flat panel that can let light go through it, or can block the light. (Unlike an LED it does not produce its own light).
The panel is made up of several blocks, and each block can be in any shape. Each block is filled with liquid crystals that can be made clear or solid, by changing the electric current to that block.
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Two charge + q and -q are situated at a certain distance. At the point exactly midway between them
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(a) Electric field and potential both are zero |
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(b) Electric field is zero but potential is not zero |
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(c) Electric field is not zero but potential is zero |
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(d) Neither electric field nor potential is zero |
In the experiment of diffraction at a single slit, if the slit width is decreased, the width of the central maximum
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(a) Increases in both Fresnel and Fraunhofer diffraction |
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(b) Decreases both in Fresnal and Fraunhofer diffraction |
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(c) Increases in Fresnel diffraction but decreases in Fraunhofer diffraction |
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(d) Decreases in Fresnel diffraction but increases is Fraunofer diffraction. |
Assertion : A loosely round helix made of stiff wire is suspended vertically with the lower end just touching a dish of mercury. When a current is passed through the wire, the helical wire executes oscillatory motion with the lower end jumping out of and inside of mercury.
Reason : When electric current is passed through helix, a magnetic field is produced both inside and outside the helix.
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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 current conduction in a discharged tube is due to
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(a) Electrons only |
(b) +ve ions and electrons |
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(c) – ve ions and electrons |
(d) + ve ions, – ve ions and electrons |
One cannot see through fog because .......... :
A radioactive sample with a half life of 1 month has the label : “Activity=2 micro curies on 1.8.1991.'' What will be its activity two months later
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(a) 1.0 micro curies |
(b) 0.5 micro curies |
(c) 4 micro curies |
(d) 8 micro curies |