I need help answering the following two questions. Please show work A typical AA

Question

I need help answering the following two questions. Please show work

A typical AA battery (NiCd) can typically store 5000 Coulombs of charge in the form of electrolytes. If the battery is short circuited (ie a bare wire connects + and - ends) it can discharge 90% of its stored energy in less than 60 seconds. What is the current in amps assuming 90% discharge in 60 seconds during this short circuit? The most dangerous aspect of short circuiting a battery is the small explosion and release of toxic metals due to rapid heating. NiCd Batteries have an operating voltage of 1.2V. Assuming the same capacity (5000 Coulombs) for the battery and assuming the batter weighs 0.05 kg and has a specific heat of Cp = 920J/kg degree C. Assuming the battery is initially at 21 degree C what will the final temperature be after discharging 90% of its power? (assuming no heat loss toot's surroundings)

Explanation / Answer

1.

Energy stored in the battery is proportional to square of the charge.therefore

E2/E1=(Q2/Q1)2

given E2=0.9E1

=>0.9=(Q2/5000)2

Q2=4743.4 Coloumbs

which is the charge discharged in 60 seconds due to short circuit ,so current

I=Q/t=4743.4/60

I=79.06 A

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