Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 3>Q 37

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A steady current flows in a metallic conductor of a non-uniform cross-section. The quantity/quantities constant along the length of the conductor is/are

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Important Questions on Current Electricity

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Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 3>Q 38

Which of the following characteristics of electrons determines the current in a conductor?

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Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 3>Q 39

A metal wire of uniform cross-sectional area

1 {mm}^{2}

has a free electron density of

6 \times 10^{28} m^{- 3}

. If the wire is carrying

0.96 A

current, what is the drift velocity of the free electrons along the wire? (Charge on electron

= 1.6 \times 10^{- 19} C

).

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Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 3>Q 40

The electron drift speed is small and the charge of the electron is also small but still, we obtain a large current in a conductor. This is due to

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Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 3>Q 41

50 V

battery is supplying a current of

10 amp

when connected to a resistor. If the efficiency of battery at this current is

25 %

. Then internal resistance of the battery is:

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Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 3>Q 42

In the circuit shown here, $E_{1} = E_{2} = E_{3} = 2 V$ and $R_{1} = R_{2} = 4 Ω$ . The current flowing between points $A$ and $B$ through battery $E_{2}$ is

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Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 3>Q 43

To get maximum current through a resistance of

2.5 Ω

, one can use

m

rows of cells, each row having

n

cells. The internal resistance of each cell is

0.5 Ω

. What are the values of

n

and

m

, respectively, if the total number of cells is

45

?

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Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 3>Q 44

n

equal cells having emf

E

and internal resistance

r

are connected in series in a circuit of resistance

R

. The same current will flow in the circuit when they are connected in parallel, if

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Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 3>Q 45

The specific resistance of manganin is

50 \times 10^{- 8} Ω m

. The resistance of a cube of length

50 cm

across two sides will be: