Electricity Test

Result

Electricity Test - 35

Score
-
out of -
Rank
-
out of -

TIME Taken - -

SHARING IS CARING

If our Website helped you a little, then kindly spread our voice using Social Networks. Spread our word to your readers, friends, teachers, students & all those close ones who deserve to know what you know now.

Weekly Quiz Competition

Question 1
1 / -0

A wire of resistance R is cut into ten equal parts which are then joined in parallel. The new resistance is:

A
0.01 R

B
0. 1 R

C
10 R

D
100 R

Solution

We know,
1. When a resistance is divided into n identical resistances, each of resistance (say R') become $$\dfrac{R}{n} $$.
2. When n identical resistors each of resistance R', are connected in parallel, the equivalent resistance is $$ \dfrac{R'}{n} $$
The resistor R, when divided into ten parts becomes resistors of resistance $$ \dfrac{R}{10} $$each.
The recombination of $$10$$ resistors, each of resistance $$ \dfrac{R}{10} $$, gives a resistor of equivalent resistance $$R'$$ of value $$\dfrac{\frac{R}{10}}{10} = \dfrac{R}{100} $$
Hence,
$$ \dfrac{R'}{R} = \dfrac{1}{100} $$
Or,
$$ R' = 0.01 R $$
Question 2
1 / -0

Two wires of resistance $$R_1$$ and $$R_2$$ are joined in parallel. The equivalent resistance of the combination is:

A
$$R_1R_2/(R_1+R_2)$$

B
$$R_1+R_2$$

C
$$R_1 \times R_2$$

D
$$R_1R_2$$

Solution

The equivalent resistance of N resistors connected in parallel connection is given by,
$$ \dfrac{1}{R^{}_{Equivalent}} = \dfrac{1}{R^{}_{1}} + \dfrac{1}{R^{}_{2}} + \dfrac{1}{R^{}_{3}} + . . . + \dfrac{1}{R^{}_{N}}$$
Hence,
$$ \dfrac{1}{R^{}_{12}} = \dfrac{1}{R^{}_{1}} + \dfrac{1}{R^{}_{2}} $$
or,
$$ R^{}_{12} = \dfrac{R^{}_{1}R^{}_{2}}{R^{}_{1} + R^{}_{2} } $$
Question 3
1 / -0

Three resistors of $$4.0\ \Omega$$, $$6.0\ \Omega$$ and $$10.0\ \Omega$$ are connected in series. What is their equivalent resistance?

A
$$20\ \Omega$$

B
$$7.3\ \Omega$$

C
$$6.0\ \Omega$$

D
$$4.0\ \Omega$$

Solution

The equivalent resistance of N resistors connected in series is given by,
$$ R^{}_{Equivalent} = R^{}_{1} + R^{}_{2} + R^{}_{3} + . . . +R^{}_{N} $$
Hence,
$$ R^{}_{Equivalent} = 4.0 + 6.0 + 10.0 = 20.0 \Omega $$
Question 4
1 / -0

Two students set up their circuits for finding the equivalent resistance of two resisto connected in series in two different ways as shown.
The circuit (s) likely to be labelled as incorrect :

A
are neither of the two circuits

B
is only circuit I

C
is only circuit II

D
are both one circuits

Solution

In correct circuit, Ammeter should linked in series whereas voltmeter should linked in parallele.
Hence circuit II is wrong
Option C
Question 5
1 / -0

A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R', then the ratio R/R' is:

A
1/25

B
1/5

C
5

D
25

Solution

We know,
1.When a resistance is divided into n identical resistances, each of resistance (say R') become $$\dfrac{R}{n} $$.
2.When n identical resistors each of resistance R', are connected in parallel, the equivalent resistance is $$ \dfrac{R'}{n} $$
The resistor R ,when divided into five parts become resistors of resistance $$ \dfrac{R}{5} $$each.
The recombination of five resistors, each of resistance $$ \dfrac{R}{5} $$, gives a resistor of equivalent resistance R' of value $$ \dfrac{\dfrac{R}{5}}{5} = \dfrac{R}{25} $$
Hence,
$$ \dfrac{R}{R'} = \dfrac{25}{1} $$
Question 6
1 / -0

Three resistances of 2, 3 and 5 $$\Omega$$ are connected in parallel to a lay battery 10V with negligible internal resistance. The potential difference across the $$3 \Omega$$ resistance will be

A
2 V

B
3 V

C
5 V

D
10 V

Solution

Emf of cell$$=E=10V$$

In parallel combination of resistors, the potential difference across each resistor is same and is equal to the potential difference between the point between which resistors are attached.

Here potential difference across $$3\Omega$$ resistor is equal to potential difference of cell $$=10V$$

Answer-(D)
Question 7
1 / -0

When a wire of uniform cross-section a, length l and resistance R is bent into a complete circle, resistance between any two of diametrically opposite points will be:

A
R/8

B
4R

C
R/2

D
R/4

Solution

$$\textbf{Step 1: Draw resistance structure}$$ $$\textbf{[Ref. Fig.]}$$
Resistance of both part will be $$R/2$$ because wire is uniform.

$$\textbf{Step 2: Equivalent resistance between A and B}$$,
Each resistor has both terminals connected to both terminals of the others so both are in parallel-

$$R_{eq \ parallel} = \dfrac{R_1R_2}{R_1+R_2}$$

$$\Rightarrow R_{AB} = \dfrac{\dfrac{R}{2}\times \dfrac{R}{2}}{\dfrac{R}{2} + \dfrac{R}{2}} = \dfrac{R}{4}$$

Hence equivalent resistance between any two of diametrically opposite points will be $$\dfrac{R}{4}$$

Option $$(D)$$ correct.
Question 8
1 / -0

Combined resistance is the sum of separate resistances provided that the various conductors are connected in______ .

A
Series

B
Parallel

C
Both series and parallel

D
Data insufficient

Solution
Question 9
1 / -0

Kilowatt-hour is the unit of :

A
potential difference.

B
electric power.

C
electrical energy.

D
charge.
Solution
- Kilowatt-hour $$(KWh)$$ is unit of Electrical Energy.
We know that, $$\text{Power} \times \text{time} = \text{Energy}$$
$$\Rightarrow\ \ \text{Kilo-Watt} \times \text{Hour} = \text{Energy}$$
- $$1 KWh$$ is electrical energy consumed when an electrical equipment of power $$1\ KiloWatt$$ is operated for $$1\ Hour$$.
- It is also used as commertial unit of energy in households/Buildings/Factories etc where 1 Unit of electricity is equivalent of 1KW-h of energy.
Hence, Option C is correct.
Question 10
1 / -0

When a fuse is rated 8A, it means :

A
It will not work if current is less than 8A

B
It has a resistance of 8 ohm

C
It will work only if current is 8A

D
It will burn if current exceeds 8A

Solution

The work of fuse wire to protect electric appliances if some particular amount of current that should not be passed through is passed accidentally.

The resistance of fuse wire is set as such if current exceeds from a particular amount heat is produced and and temperature of the fuse wire increases and it reaches to it's melting point and it melts and circuit becomes an open circuit.

So if a wire is rated 8 A, it means the resistance is set to such a value that if current is exceeded from 8 A value then fuse wire will melt down.

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

Electricity Test - 35

Result

Electricity Test - 35

Score

-

Rank

-

SHARING IS CARING

Question 1

0.01 R

0. 1 R

10 R

100 R

Solution

Question 2

$$R_1R_2/(R_1+R_2)$$

$$R_1+R_2$$

$$R_1 \times R_2$$

$$R_1R_2$$

Solution

Question 3

$$20\ \Omega$$

$$7.3\ \Omega$$

$$6.0\ \Omega$$

$$4.0\ \Omega$$

Solution

Question 4

are neither of the two circuits

is only circuit I

is only circuit II

are both one circuits

Solution

Question 5

1/25

1/5

5

25

Solution

Question 6

2 V

3 V

5 V

10 V

Solution

Question 7

R/8

4R

R/2

R/4

Solution

Question 8

Series

Parallel

Both series and parallel

Data insufficient

Solution

Question 9

potential difference.

electric power.

electrical energy.

charge.

Solution

Question 10

It will not work if current is less than 8A

It has a resistance of 8 ohm

It will work only if current is 8A

It will burn if current exceeds 8A

Solution

User

Question Analysis

My Perfomance

Score

-

Rank

-

Results Announcement on: coming Monday

Stay Tuned: We’ll update you on your result via email or SMS.