general exam on chapter one sec 3 physics

when a radius of a conductor increased to double its original value, then its resistance ........... its original value.

• the same

• decreased to double

• decreased to quarter

• increased to double

• increased four times

A copper wire is stretched to increase its length to double its value, so its resistivity ................. its original value.

• the same

• increased to double

• decreased to half

• decreased to quarter

law of conservation of the electric charge is

• ohm,s law

• Kirchhoff, first law

• Kirchhoff,s second law

• Ampere circular law

Three resistors 10 ohm,20 ohm and 40 ohm are connected together with an electric source of internal resistance 2 ohm, where the current passing through them is o.4 A,     0.5 A and 0.1 A respectively ,then the e.m.f of the source ...    

• 12 V

• 14 V

• 15 V

• no correct answer

Three resistors 4 ohm, 6 ohm and 3 ohm,are connected together in series to a battery of e.m.f 30 V and internal resistance 2 ohm. then the current of the circuit is .......

• 15 A

• 13 A

• 4 A

• 2 A

A metal wire of length 30 m and cross sectional area 0.3 m² and its resistivity 5 X 10 ^-7 ohm.m is connected in series with resistance 8.5 ohm and a battery of e.m.f 18 V, and internal resistance 1 ohm. then the electric current passing in the circuit equal ....

• 1.8 A

• 1.5 A

• 1 A

• 0.5 A

Three equal resistors of 3 ohm each, are connected in series to a cell of internal resistance 1 ohm. If this resistances are connected in parallel and connected to the same cell, then the ratio of the respective current through the electric circuits in the two cases is .........

• 1:8

• 1:7

• 1:5

• 1:3

In the opposite circuit, if the ammeter reading is 2 A, then the value of the resistance R is ..... ohm.

• 6

• 4

• 3

• 2

In the opposite figure , if the internal resistance of of each cell is 2 ohm, then the total electric current in the circuit ...

• 1.5 A

• 1 A

• 0.75 A

• 0.5 A

by using Kirchhoff,s laws in the opposite circuit the values of the electric currents I₁ , I₂ , I₃ respectively are ... A, ...A ,..A

• 0.6 A, 0.96 A and 0.36 A

• 0.96 A, 0.36 A, and 0.6 A

• 0.36 A, 0.96 A and 0.6 A

• 0.6 A, 0.36 A, and 0.96 A