Question

dry cell can supply charge of 50 C. If the current draws from the cell is 750 uA, find the time in which the cell completely
discharges.​

Answer 1

• 66666.66 Seconds

Explanation:

Given:-

• Current ,I = 750 uA

• Charge ,Q = 50 C

To Find:-

• Time in which the cell discharge ,t

Solution:-

Conversion of Unit

1 ampere = 1000000 uA

Therefore, 750uA = 750/1000000 A = 0.00075 A

As we know that current is defined as the flow of charges per unit time.

• I = Q/t

→ t = Q/I

Where,

• t denote time
• Q denotes charge
• I denotes current.

Substitute the value we get

→ t = 50/0.00075

→ t = 50×100000/75

→ t = 5000000/75

→ t = 66666.66 s

• Hence, the time in which the cell Completely discharge is 66666.66 Second.

Answer 2

${\bold{\sf{\underline{Understanding \: the \: question}}}}$

✠ This question says that a dry cell can supply 50 C. Now this question says that the current draws from the cell is 750 uA. Now this say that we have to find the time in which the cell completely discharges.

${\bold{\sf{\underline{Given \: that}}}}$

✺ Dry cell can supply 50 C

✺ Current draws from the cell is 750 uA

${\bold{\sf{\underline{To \: find}}}}$

✺ Time in which the cell completely discharges.

${\bold{\sf{\underline{Solution}}}}$

✺ Time in which the cell completely

discharges = 66666.66 seconds

${\bold{\sf{\underline{Using \: concept}}}}$

✠ Formula to find current.

${\bold{\sf{\underline{Using \: formula}}}}$

✠ Current = Q/t

${\bold{\sf{\underline{We \: also \: write \: these \: as}}}}$

✠ Current as I.

✠ Charge as Q.

✠ Time as t.

${\bold{\sf{\underline{Some \: procedure \: for \: easy \: understanding}}}}$

✺ To solve this question we have to use the formula to find Current but we have to find time nor current so we have to reverse the formula. But there is a twist and it is that the unit is in uA of current draws from the cell as 750 uA. But we have to convert it into A ( Converting.... ) Now we have to use formula ( Put values ) and we get our final result very easily and it's 66666.66 seconds.

${\bold{\sf{\underline{Full \: solution}}}}$

☃ Converting uA into A

~ Current draws from the cell = 750 uA

↦ As we already know that 1 A is always equal to 1000000 uA

↦ Henceforth, 1 uA = 1/1000000 A

[ Putting the values according to ques ]

↦ That's why 750/1000000

↦ 0.00075 A

☃ Finding the time in which the cell completely discharges.

~ I = Q/t

Finding current using this formula

~ t = Q/l

↦ t = 50 / 0.00075

↦ t = 50 × 100000 / 75

↦ t = 5000000 / 75

↦ t = 66666.66 seconds

• Henceforth, 66666.66 seconds is the time in which the cell completely discharges.