A piece of copper and another of germanium are cooled from room temperature to 80 K . The resistance of...

copper decreases and germanium increases

copper increases ∧ germanium decreases

Copper and Silicon are cooled from 300 K to 60 K . The specific resistance

decreases in copper but increases in silicon

increases in copper but decreases in silicon

Constantan wire is used in making standard resistances because its

temperature coefficient of resistance is negligible

E M B I B E

Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 3>Q 26

MEDIUM

NEET

IMPORTANT

Earn 100

What is the time $t$ taken by the capacitor in the given circuit to charge to $\frac{1}{\sqrt{2 π}}$ of its full capacity?

54.84% studentsanswered this correctly

Important Questions on Current Electricity

EASY

NEET

IMPORTANT

Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 3>Q 27

Two batteries, one of emf 18 volts and internal resistance $2 Ω$ and the other of emf 12 volst and internal resistance $1 Ω$ , are connected as shown. The voltmeter V will record a reading of :-

Question Image

MEDIUM

NEET

IMPORTANT

Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 3>Q 28

Electric resistance is defined as the ratio of voltage to current. Its dimensional formulae is given by

MEDIUM

NEET

IMPORTANT

Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 3>Q 29

In a meter bridge experiment, the circuit diagram and the corresponding observation table are shown in figure.
Question Image

S. No.	$R (Ω)$	$l (c m)$
_1. _2. _3. _4.	$1000$ $100$ $10$ $1$	$60$ $13$ $1.5$ $1.0$

Which of the reading is inconsistent?

MEDIUM

NEET

IMPORTANT

Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 3>Q 30

In a meter bridge experiment resistances are connected as shown in the figure. Initially resistance

P = 4 Ω

and the neutral point

N

is at

60 cm

from

A

. Now an unknown resistance

R

is connected in series to

P

and the new position of the neutral point is at

80 cm

from

A

. The value of unknown resistance

R

is -

MEDIUM

NEET

IMPORTANT

Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 3>Q 31

In a meter bridge as shown in the figure, it is given that resistance

Y = 12.5 Ω

and that the balance is obtained at a distance

39.5 cm

from end

A

(by jockey

J

). After interchanging the resistances

X

and

Y

a new balance point is found at a distance

l_{2}

from end

A

. What are the values of

X

(in

Ω

) and

l_{2}

?

MEDIUM

NEET

IMPORTANT

Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 3>Q 32

A

200 Ω

resistor has certain colour code. If one replaced the red colour by green in the code, the new resistance will be:

EASY

NEET

IMPORTANT

Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 3>Q 33

A uniform metallic wire has a resistance of

18 Ω

and is bent into an equilateral triangle. Then, the resistance between any two vertices of the triangle is:

EASY

NEET

IMPORTANT

Physics Crash Course NEET>Chapter 13 - Current Electricity>Level 3>Q 34

In the figure, a carbon resistor has bands of different colours on its body as mentioned in the figure. The value of the resistance is:
Question Image