Ch(1) lessons (1 - 2 - 3)

اسمك ايه يا عم:

1- In the opposite electric circuit, the reading of the ammeter (A) equals

• 1 A
• 2 A
• 3 A
• 4 A

2- The opposite figure represents a part of an electric circuit, if the ammeter reading equals zero, the value of the resistor R equals

• 8 ohm
• 9 ohm
• 12 ohm
• 24 ohm

3- The cross-sectional area of a cylindrical rod is 3 cm^2 and its resistance is 5 ohm. It has been drawn uniformly until its cross-sectional area becomes 0.75 cm^2, so its resistance becomes

• 80 ohm
• 60 ohm
• 40 ohm
• 20 ohm

4- In the opposite electric circuit, three identical electric bulbs are glowing. When the switch K is closed then the light of the bulb A

• Remains unchanged
• Vanishes
• Decreases
• Increases

5- Two resistors have resistances of 10 Ω and R, the consumed power through them when they are connected in parallel with a battery of negligible internal resistance is four times the power consumed through them when they are connected in series with the same battery, then the value of R equals

• 10 ohm
• 7.5 ohm
• 5 ohm
• 2.5 ohm

6- If the electric current intensity through a conductor is 2 A, the quantity of charge that passes through a cross-section of this conductor in a minute is

• 120 C
• 60 C
• 30 C
• 2 C

7- In the following electric circuit, there is a lamp connected to a battery. A charge of 4 C passes through the lamp in 2 sec. Which row represent the right answer?

• From left to right, 2 A
• From left to right, 8 A
• From right to left, 2 A
• From right to left, 8 A

8- 6.25×10^18 electron passes in 1 second through a conductor of cross-section area 0.1 m^2 then the current intensity in the conductor equals

• 1 A
• 0.3 A
• 10 A
• 0.11 A

9- Two wires of the same material the length of the first is 2L and its radius is r while the length of the second is L and its radius is 2r as in the following figure. which of the following sentences is right?

• V(wire 1)=2V(wire 2)
• P(wire 1)=4P(wire 2)
• I1=I2
• R1=4R2