Question

A charge of 15 C flows from a battery for 5 s and 90 J of energy is supplied to a lamp bulb connected across the battery. Calculate 

 (a)the current through the bulb

 (b) the potential difference across the bulb.

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Answer 1

Answer:

• (a) 3 ampere
• (b) 6 volts

Explanation:

Given:-

• Charge ,Q = 15 C
• Time taken ,t = 5 s
• Energy ,E = 90 J

To Find:-

• Current ,I
• Potential Difference,V

Solution:-

Firstly we calculate the Current through the bulb .

As we know that Current is defined as the rate of flow of charges at per unit time.

• I = Q/t

Where,

• I denote Current
• Q denote Charge
• t denote time

Substitute the value we get

→ I = 15/5

→ I = 3 A

• Hence, the Current through the bulb is 3 ampere.

Now, we have to calculate the Potential Difference across the Bulb.

• E = VIt

where,

• E denote Energy Consumed
• V denote Potential Difference
• I denote Current
• t denote time taken

Substitute the value we get

→ 90 = V × 3 × 5

→ 90 = V× 15

→ V = 90/15

→ V = 6 v

• Hence, the Potential Difference across the bulb is 6 volts.

Answer 2

Answer:

Given :-

• Charge = 15 C
• Time = 5 sec
• Energy = 90 J

To Find :-

• Current
• Potential Difference

Solution :-

As we know that

$\large \bf \: I = \dfrac{Q}T$

I is the Current

Q is the Charge

T is the Time

$\large \sf \: I = \dfrac{15}{5}$

$\large \sf \: I =3 \: ampere$

Now,

Finding Potential Difference

$\large \bf \: E = VIT \:$

• E is the Energy consumed
• V is the Potential Difference
• I is the Current
• T is the Time taken

$\large \sf \: 90 = (V)(3)(5)$

$\large \sf \: 90 = 15 V$

$\large \sf \: V = \dfrac{90}{15}$

$\frak \pink{ V = 6 \: volts}$