Current Electricity

1. Find the emf of cell which balance against a length of 280cm of potentiometer wire , given potential difference per cm wire as 0.008

• 1.08 V
• 2.04 V
• 2.24 V
• 3.25 V

2. Using Kirchhoff laws, find the currents of the network

• I1 =48/31 , I2 =66/31, I3 =18/31
• I1 =18/31 , I2 =26/31, I3 =18/31
• I1 =22/13 , I2 = -6/13, I3 =28/13
• none of these

3. A potentiometer having wire 1000cm long stretched on it is connected to a battery having a steady voltage , A Daniel cell gives a null point at 400cm. if the length of potentiometer wire increased by 200cm find the new position of null point

• 360cm
• 400cm
• 440cm
• 480cm

4. A 4.0 V potentiometer used for the determination of internal resistance of a 2.5 V cell. The balance point of the cell in open circuit is 96.3 cm. When a resistor of 12.5 Ω is used in the external circuit of the cell, the balance point shifts to 76.8 cm length of the potentiometer wire. Determine the internal resistance of the cell.

• 3.125 ohm
• 2.125 ohm
• 1.125 ohm
• 0.125 ohm

5. Twelve identical wires of resistance 4 ohm , are joined to form a skeleton cube. The Current enters at one corner and leaves at the diagonally opposite corner find the total resistance between these corners

• 1.33ohm
• 2.33ohm
• 3.33ohm
• 4.33ohm

6. How much current will heater rated 2.5KW draw, when connected to 250V supply

• 40A
• 30A
• 20A
• 10A

Tags

NGSS.HS-PS3-1

7. A heater is rated as 220 volt 880 watt , what is the current drawn by heater when connected to 220volt ac main , calculate resistance of heater

• 25ohm
• 35ohm
• 45ohm
• 55ohm

8. A room heater is marked as 1000watt -200V, find the percentage change in the power of heater if voltage drops 120V

• 36%
• 54%
• 64%
• 72%

Tags

NGSS.HS-PS3-1

9. The storage battery of a car has an emf of 8 V , if the internal resistance of battery 0.8 ohm , what is the maximum current that can be drawn from the battery

• 10A
• 20A
• 30A
• 40A

10. What is internal resistance of 2.0V cell which gives a current 0.1A through resistance of 10ohm

• 10 ohm
• 20 ohm
• 30 ohm
• 40 ohm