# Two ideal diodes are connected to a battery as shown in the circuit. The current supplied by the battery is:      1. $$0.75~\text{A}$$ 2. zero 3. $$0.25~\text{A}$$ 4. $$0.5~\text{A}$$

Subtopic:  PN junction |
86%
From NCERT
AIPMT - 2012
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$${C}$$ and $${Si}$$ both have the same lattice structure, having $$4$$ bonding electrons in each. However, $$C$$ is an insulator whereas $$Si$$ is an intrinsic semiconductor. This is because:
 1 in the case of $$C$$, the valence band is not completely filled at absolute zero temperature. 2 in the case of $$C$$, the conduction band is partly filled even at absolute zero temperature. 3 the four bonding electrons in the case of $$C$$ lie in the second orbit, whereas in the case of $$Si$$, they lie in the third. 4 the four bonding electrons in the case of $$C$$ lie in the third orbit, whereas for $$Si$$, they lie in the fourth orbit.
Subtopic:  Energy Band theory |
71%
From NCERT
NEET - 2012
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The figure shows a logic circuit with two inputs $$A$$ and $$B$$ and the output $$C$$. The voltage waveforms across $$A$$, $$B$$, and $$C$$ are as given. The logic circuit gate is:

1. $$\text{OR}$$ gate
2. $$\text{NOR}$$ gate
3. $$\text{AND}$$ gate
4. $$\text{NAND}$$ gate

Subtopic:  Logic gates |
83%
From NCERT
AIPMT - 2012
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The symbolic representation of four gates is shown as:

Pick out which ones are for AND, NAND, and NOT gates, respectively.

1.  (i), (iv), and (iii)

2.  (ii), (iii), and (iv)

3.  (ii), (iv), and (iii)

4.  (ii), (iv), and (i)

Subtopic:  Logic gates |
88%
From NCERT
AIPMT - 2011
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If a small amount of antimony is added to germanium crystal:

 1 the antimony becomes an acceptor atom 2 there will be more free electrons than holes in the semiconductor 3 its resistance is increased 4 it becomes a $$p\small{-}$$type semiconductor

Subtopic:  Types of Semiconductors |
82%
From NCERT
AIPMT - 2011
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In a forward biasing of the p-n junction:

 1 the positive terminal of the battery is connected to the p-side and the depletion region becomes thick. 2 the negative terminal of the battery is connected to the n-side and the depletion region becomes thin. 3 the positive terminal of the battery is connected to the n-side and the depletion region becomes thin. 4 the negative terminal of the battery is connected to the p-side and the depletion region becomes thick.

Subtopic:  PN junction |
74%
From NCERT
AIPMT - 2011
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Which one of the following statements is false?

 1 Pure Si doped with trivalent impurities gives a p-type semiconductor. 2 The majority of carriers in an n-type semiconductor are holes. 3 The minority carriers in a p-type semiconductor are electrons. 4 The resistance of intrinsic semiconductors decreases with an increase in temperature.

Subtopic:  Types of Semiconductors |
86%
From NCERT
AIPMT - 2010
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To get an output Y = 1 from the circuit shown below, the input must be:

1. A=0 B=1 C=0

2. A=0 B=0 C=1

3. A=1 B=0 C=1

4. A=1 B=0 C=0

Subtopic:  Logic gates |
91%
From NCERT
AIPMT - 2010
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$$\mathrm{p\text-n}$$ photodiode is fabricated from a semiconductor with a band gap of $$2.5$$ eV. It can detect a signal of wavelength:
1. $$6000~\mathring{A}$$
2. $$4000$$ nm
3. $$6000$$ nm
4. $$4000~\mathring{A}$$
Subtopic:  Energy Band theory |
63%
From NCERT
AIPMT - 2009
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The symbolic representation of four logic gates is as shown:

 (i) (ii) (ii) (iv)

The logic symbols for OR, NOT, and NAND gates are respectively:
1. (iii), (iv), (ii)
2. (iv), (i), (iii)
3. (iv), (ii), (i)
4. (i), (iii), (iv)

Subtopic:  Logic gates |
91%
From NCERT
AIPMT - 2009
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