will be very kind if reply for the answer myself yogesh from village tilpat in Faridabad

we know that

the relation between terminal voltage (V) and emf (E) of a battery is given as

V = E - Ir

here,

E = 12 volts

I = 90 amps

r = 0.05 ohms

so,

V = 12 - 90x0.05

thus, terminal voltage

V = 7.5 volts

now,

the maximum current will be calculated for a short circuit when voltage is zero

so, if V = 0

E = Ir

or

Imax = E/r

here,

r = 500 ohms

so,

Imax = 12/500

thus, maximum current

Imax = 0.024 amps