Physics 3rd year 4

which of the following leads to the increase of the current intensity through an electric circuit to the double ?

• The increase of electromotive force of the battery to the double .

• The decrease of the electromotive force of the battery to the double .

• The increase of the resistance ( R ) in the circuit to the double .

• The decrease of the resistance ( R ) in the circuit to the quarter .

The opposite figure represents a part of an electric circuit . If the voltmeter reads (1 V) , then the potential difference between the two points "X" and "Y" equals ...........................

• 1 V

• 2 V

• 3 V

• 4 V

• 6 V

• 7.5 V

• 9 V

• 12 V

• 3.5 A

• 2.5 A

• 2 A

• 1.5 A

If the potential difference between A and B in the opposite electric circuit equals (4 V) , then the value of resistance (R) equals ..........................

• 2 A

• 4 A

• 6 A

• 8 A

In the opposite figure , two long straight wires are perpendicular to each other , while the shortest distance between them is (20 cm). If the first wire carries (20 A) in perpendicular direction out of the page and the second wire carries a current of (15 A) in a direction parallel to the page , the net magnetic flux density at point "X" will be ............