Electricity Test

Result

Electricity Test - 31

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

If the equivalent resistance is to be increased, then the number of resistances should be connected in:

A
Series

B
Parallel

C
Mixed arrangement

D
None of the above

Solution

Equivalent resistance is maximum and current flow is minimum when number of resistances are connected in series.$$R_{eq}= R_1 + R_2 + R_3$$ ; where $$R_1,R_2,R_3$$ are resistances.
Question 2
1 / -0

Why is electrical wiring usually made from copper?

A
Because copper is shiny.

B
Because copper conducts electricity.

C
Because copper is not magnetic

D
none of these

Solution

Materials that allow an electric current to pass through them are called
conductors. Copper is a good conductor of electricity. The electrical wiring usually made from copper because copper conducts electricity.
Question 3
1 / -0

The equivalent resistance due to series connection of $$10\ \Omega$$ and $$10\ \Omega$$ resistors is

A
$$5\ \Omega$$

B
$$10\ \Omega$$

C
$$0\ \Omega$$

D
$$20\ \Omega$$

Solution

For series connection(Current remains same):
$$R_{ (total)} = R_1 + R_2$$
In series combination equivalent resistance is total sum of the resistances.
$$\Rightarrow R_{total}=10+10$$
$$\Rightarrow R_{total}=20\Omega $$
Question 4
1 / -0

In any electric circuit, when the switch is on and the current is flowing through it why do the wire, switches, bulb or devices in the circuit become hot?

A
Because of the heating effect of electric current

B
Because of the magnetic effect of electric current

C
Because of the luminous effect of electric current

D
None of these

Solution

This is because some of the electric energy is converted into heat energy, i.e., heating effect of electric current.
Question 5
1 / -0

In the series combination of two or more than two resistances.

A
The current through each resistance is same

B
The voltage through each resistance is same

C
Neither current nor voltage through each resistance is same

D
Both current and voltage through each resistance are same

Solution

For resistances in series, the current through each resistors remains the same.
Question 6
1 / -0

A light bulb is rated at 100 W for a 220 V ac supply. The resistance of the bulb is then

A
$$284

\Omega$$

B
$$384

\Omega$$

C
$$484

\Omega$$

D
$$584 \Omega$$

Solution

Here, P = 100 W , $$V \, = \, 220 \, V $$
Resistance of the bulb is
$$R \, = \, \dfrac{V^{2}}{P} \, = \, \dfrac{(220)^2}{100} \, = \, 484 \, \Omega$$
Question 7
1 / -0

If five equal pieces of $$25\Omega$$ are connected in parallel, then their equivalent resistance will be............

A
$$25\Omega$$

B
$$1\Omega$$

C
$$5\Omega$$

D
$$\dfrac{1}{5}\Omega$$

Solution

Resistance of each piece :
$$R_1 = R_2=R_3=R_4 = R_5 = 25 \ \Omega$$
Equivalent resistance in parallel
$$\dfrac{1}{R_p} = \dfrac{1}{R_1}+\dfrac{1}{R_2} +\dfrac{1}{R_3}+\dfrac{1}{R_4}+\dfrac{1}{R_5}$$
$$\therefore$$ $$\dfrac{1}{R_p} = \dfrac{1}{25}+\dfrac{1}{25} +\dfrac{1}{25}+\dfrac{1}{25}+\dfrac{1}{25}$$
$$\implies \ \dfrac{1}{R_p} = \dfrac{5}{25}$$
We get,
$$R_p = 5\Omega$$
Question 8
1 / -0

In a house, individual powers of two elements are $$100\ W\ 100\ W$$. The effective power of their series combination will be :

A
$$120\ W$$

B
$$75\ W$$

C
$$50\ W$$

D
$$60\ W$$

Solution

$$\begin{array}{l}I = \dfrac{V}{{{R_1}}}\\{I^2}R = 100\\I' = \dfrac{V}{{{R_2}}}\\I{'^2}{R_2} = 150\\{R_1} = \dfrac{{100}}{{{I^2}}}\\{R_1} = \dfrac{{100}}{{{{\left( {V/{R_1}} \right)}^2}}}\\{R_1} = \dfrac{{{V^2}}}{{100}}\\{R_2} = \dfrac{{{V^2}}}{{150}}\\{R_1} + {R_2} = {V^2}\left( {\dfrac{1}{{100}} + \dfrac{1}{{150}}} \right)\\{R_3} = {V^2}\dfrac{5}{{100}} = \dfrac{{{V^2}}}{{60}}\\effective\,power = \dfrac{{{V^2}}}{{{R_3}}} = \dfrac{{{V^2}}}{{\left( {{V^2}/60} \right)}} = 60W\end{array}$$
Question 9
1 / -0

Combine three resistors $$5\Omega, 4.5\Omega$$ and $$3\Omega$$ in such a way that the total resistance of this combination is maximum:

A
$$12.5\Omega$$

B
$$13.5\Omega$$

C
$$14.5\Omega$$

D
$$16.5\Omega$$

Solution

Given resistance,
$$R_1=5\Omega\\R_2=4.5\Omega\\R_1=3\Omega$$

In series combination effective resistance will be maximum.
ie, $$R_{eq}=R_1+R_2+R_3$$
$$R_{eq}=5 \Omega + 4.5 \Omega + 3 \Omega = 12.5 \Omega$$

Option A
Question 10
1 / -0

The smallest resistance that can be obtained by combining 10 resistors each of resistance $$10 \Omega$$ is

A
$$10\Omega$$

B
$$0.5\Omega$$

C
$$2\Omega$$

D
$$20\Omega$$

E
$$1\Omega$$

Solution

When the resistors are connected in parallel combination, the equivalent resistance will decrease. Thus, if the 10 resistors are connected in parallel, we will get minimum resistance.
Thus, $$\dfrac{1}{R_{eq}}=\dfrac{n}{R}$$ where $$n=10$$ number of resistors which have same resistance and $$R=10 \Omega$$ resistance of each resistor.
So, $$\dfrac{1}{R_{eq}}=\dfrac{10}{10}$$
or $$R_{eq}=1$$

User

Question Analysis

Correct -
Wrong -
Skipped -

My Perfomance

Score
-
out of -
Rank
-
out of -

Re-Attempt Weekly Quiz Competition

Electricity Test - 31

Result

Electricity Test - 31

Score

-

Rank

-

SHARING IS CARING

Question 1

Series

Parallel

Mixed arrangement

None of the above

Solution

Question 2

Because copper is shiny.

Because copper conducts electricity.

Because copper is not magnetic

none of these

Solution

Question 3

$$5\ \Omega$$

$$10\ \Omega$$

$$0\ \Omega$$

$$20\ \Omega$$

Solution

Question 4

Because of the heating effect of electric current

Because of the magnetic effect of electric current

Because of the luminous effect of electric current

None of these

Solution

Question 5

The current through each resistance is same

The voltage through each resistance is same

Neither current nor voltage through each resistance is same

Both current and voltage through each resistance are same

Solution

Question 6

$$284 \Omega$$

$$384 \Omega$$

$$484 \Omega$$

$$584 \Omega$$

Solution

Question 7

$$25\Omega$$

$$1\Omega$$

$$5\Omega$$

$$\dfrac{1}{5}\Omega$$

Solution

Question 8

$$120\ W$$

$$75\ W$$

$$50\ W$$

$$60\ W$$

Solution

Question 9

$$12.5\Omega$$

$$13.5\Omega$$

$$14.5\Omega$$

$$16.5\Omega$$

Solution

Question 10

$$10\Omega$$

$$0.5\Omega$$

$$2\Omega$$

$$20\Omega$$

$$1\Omega$$

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.

$$284

\Omega$$

$$384

\Omega$$

$$484

\Omega$$