Tag: effects of electric current

Questions Related to effects of electric current

A current of $4  A$ flows through a $12  V$ car headlight bulb for $10$ minutes, how much energy is consumed?

physics effects of electric current thermal effect of electric current heating effect of electric current electric current and its effects

  1. $8 \times {10}^{-3} kwh$

  2. $48 kwh$

  3. $8 kwh$

  4. $8 \times {10}^{3} kwh$

Show answer
Correct Option: A
Explanation:

$E = VIt$
  $= 12 \times 4 \times \dfrac{1}{6}$
  $= 8 \times {10}^{-3}   kwh$

Calculate the monthly bill if a heater of 100 watt is used at the rate of rs. 1 per unit for 1 hour daily.

physics effects of electric current thermal effect of electric current heating effect of electric current electric current and its effects

  1. Rs. 200

  2. Rs. 6000

  3. Rs. 100

  4. Rs. 3

Show answer
Correct Option: D
Explanation:

Given :       $P=0.1$ kW           $t = 1$ hour per day

Energy consumed per day     $E = Pt = 0.1\times 1 = 0.1$ kWh per day
Total energy consumed per month  $E _T = 30\times 0.1 = 3$ kWh per month
Cost of electricity  $ =Re$ $ 1 $ per unit i.e per kWh
$\therefore$  Monthly bill $ = Re.$ $1\times 3   =$Rs. $3$ per month

What should be the bill for the month of March for a heater of resistance $\displaystyle $ connector to 220V mains. The cost of energy is Rs.1 kWh and the heater is used 1 hour daily.

physics effects of electric current thermal effect of electric current heating effect of electric current electric current and its effects

  1. Rs. 144

  2. Rs. 60

  3. Rs. 72

  4. Rs. 50

Show answer
Correct Option: C

Calculate the total power of 2 fans, if each of them draws a current of $5   A$ at a p.d of $200   V$.

physics effects of electric current thermal effect of electric current heating effect of electric current electric current and its effects

  1. $2000 \omega$

  2. $1000 V$

  3. $250 \omega$

  4. $2 \omega$

Show answer
Correct Option: A
Explanation:

$I = 5A,   p.d = 200   V$
Power $= V \times I = 200 \times 5 = 1000   \omega$
For 2 fans $= 2 \times 1000 = 2000   \omega$.

A current of $0.5  A$ flows through a resistance of $10  \Omega$ for $\dfrac{1}{2}$ hour. Find the amount of electrical energy consumed by resistance.

physics effects of electric current thermal effect of electric current heating effect of electric current electric current and its effects

  1. $450 J$

  2. $4500 J$

  3. $45 J$

  4. $45000 J$

Show answer
Correct Option: B
Explanation:

$E = {I}^{2}RT = {0.5}^{2} \times 10 \times 1800$
       $= 4500  J$

Calculate the energy transferred by a $5  A$ current flowing through a resistor of $20   \ ohms$ for $30$ minutes.

physics effects of electric current thermal effect of electric current heating effect of electric current electric current and its effects

  1. $25 kwh$

  2. $50 kwh$

  3. $2.5 \times {10}^{-2} kwh$

  4. $5 \times {10}^{-2} kwh$

Show answer
Correct Option: C
Explanation:

$E = {I}^{2}Rt$
$= {5}^{2} \times 2 \times \dfrac{1}{2}$
$= 2.5 \times {10}^{-2}  kwh$

An electric bulb is rated $750   \omega - 200   V$. Calculate the magnitude of current.

physics effects of electric current thermal effect of electric current heating effect of electric current electric current and its effects

  1. $200 A$

  2. $3.75 A$

  3. $15 A$

  4. $2 A$

Show answer
Correct Option: B
Explanation:

$V = 200   V,   P = 750   \omega$.
$P = VI ,   750 = 200 \times I$
$I = 3.75   A$.

An electric bulb of resistance $480  \Omega$ is connected to $220  V$. Find electric energy consumed in $10  s$.

physics effects of electric current thermal effect of electric current heating effect of electric current electric current and its effects

  1. $1000 J$

  2. $9600 J$

  3. $1008.3 J$

  4. $1118.7 J$

Show answer
Correct Option: C
Explanation:

$E = \dfrac{{V}^{2}t}{R}$
  $= \dfrac{{\left(200\right)}^{2} \times 10}{480}  =  1008.3  J$

A bulb of $2.5  V$, draws a current of $0.5  A$. If the bulb is switched on for 2 minutes, calculate the energy released by the bulb.

physics effects of electric current thermal effect of electric current heating effect of electric current electric current and its effects

  1. $1.25 J$

  2. $260 J$

  3. $5 J$

  4. $150 J$

Show answer
Correct Option: D
Explanation:

P.D $= 2.5   V$
Current $= 0.5   A$
$t = 2$ minute $= 2 \times 60 = 120  s$
$ E = V \times I \times t = 2.5 \times 0.5 \times 120 = 150   J$.

A light bulb has the resistance of tungsten resistance which convert about 10% electrical energy into visible light.  If energy other than visible is waste energy. How many kilo-joules does a light bulb wasted in one hour?

physics effects of electric current thermal effect of electric current heating effect of electric current electric current and its effects

  1. 36 kJ

  2. 90 kJ

  3. 3240 kJ

  4. 360 kJ

  5. 32,400 kJ

Show answer
Correct Option: C
Explanation:
$90$ % of electrical energy is wasted in one hour.
Using        $1kWh  = 3600$ $kJ$
$\therefore$ Energy wasted       $E _{waste} = 0.9 \times 3600  =3240$  $kJ$