given

length L = 40 cm

= 0.40 m

breadth B = 20 cm

=0.20 m

thickness t = 10 cm

= 0.10 m

Voltage V = 6.0 V

area A = (L)(B)

we want to find the current

we have given voltage (V) and sides of the rectangular box

we can proceed with ohms law V=(I)(R)

here resistance (R) is unknown

from theory when the length and area are given we have the equation for resistance as

R = ?(L/A)

where ? is the specific resistance of thematerial, (L) is the length, and (A) is the area of the

rectangular box

as the rectangular box has three sides we havethree values of (L/A)

with 0.6 m, 0.22 m, 0.44 m

a) from those values of (L/A) choose minimumvalue of (L/A) and substitute in \(\displaystyle{I}_{{\max}}={\frac{{{V}}}{{{R}_{{\min}}}}}\)

\(\displaystyle={\frac{{{V}}}{{{\left(?{\frac{{{L}}}{{{A}}}}\right)}_{{\max}}}}}\)

b) from those values of (L/A) choose maximumvalue of (L/A) and substitute in

\(\displaystyle{I}_{{\min}}={\frac{{{V}}}{{{R}_{{\max}}}}}\)

\(\displaystyle={\frac{{{V}}}{{?{\left({\frac{{{L}}}{{{A}}}}\right)}_{{\max}}}}}\)

length L = 40 cm

= 0.40 m

breadth B = 20 cm

=0.20 m

thickness t = 10 cm

= 0.10 m

Voltage V = 6.0 V

area A = (L)(B)

we want to find the current

we have given voltage (V) and sides of the rectangular box

we can proceed with ohms law V=(I)(R)

here resistance (R) is unknown

from theory when the length and area are given we have the equation for resistance as

R = ?(L/A)

where ? is the specific resistance of thematerial, (L) is the length, and (A) is the area of the

rectangular box

as the rectangular box has three sides we havethree values of (L/A)

with 0.6 m, 0.22 m, 0.44 m

a) from those values of (L/A) choose minimumvalue of (L/A) and substitute in \(\displaystyle{I}_{{\max}}={\frac{{{V}}}{{{R}_{{\min}}}}}\)

\(\displaystyle={\frac{{{V}}}{{{\left(?{\frac{{{L}}}{{{A}}}}\right)}_{{\max}}}}}\)

b) from those values of (L/A) choose maximumvalue of (L/A) and substitute in

\(\displaystyle{I}_{{\min}}={\frac{{{V}}}{{{R}_{{\max}}}}}\)

\(\displaystyle={\frac{{{V}}}{{?{\left({\frac{{{L}}}{{{A}}}}\right)}_{{\max}}}}}\)