Question

A copper transmission cable of length 100km and 10 cm in diameter

Answer 1

To determine: (a) Potential drop across the cable.(b) Electrical energy dissipated per hour.Answer: (a) Potential drop across the cable is. (b) Electrical energy dissipated per hour is. Explanation:(a)Area of the wire is,Resistance of wire is, Here, is the resistivity, is the cross section area and is the length of the wire.Value of the resistance of wire is, Potential drop across the cable.Hence, potential drop across the cable is.(b)Electrical energy dissipated per second is,Electrical energy dissipated per hour is,Therefore, Electrical energy dissipated per hour is.

To determine: (a) Potential drop across the cable. (b) Electrical energy dissipated per hour. Answer: (a) Potential drop across the cable is 27.37 V. (b) Electrical energy dissipated per hour is 12.32 MJ. Explanation: (a) Area of the wire is, 223220.10 m27.8 10 mdA−= = = Resistance of wire is, lRA = Here,R is the resistivity, Ais the cross section area and lis the length of the wire. Value of the resistance of wire is, ( )85321.72 10 m 10 m7.8 10 m0.2189 R−− = = Potential drop across the cable. ( )( )125 A 0.2189 =27.37 VV IR= = Hence, potential drop across the cable is 27.37 V. (b) Electrical energy dissipated per second is, ( )( )27.37 V 125 A3421.8 WP VI= == Electrical energy dissipated per hour is, ( )3421.8 W 3600 s12.32 MJE Pt= == Therefore, Electrical energy dissipated per hour is12.32 MJ