Resistance and Ohm's Law

Q.

A piece of wire having resistance 'R' is cut into four equal parts.

a) How does the resistance of each part compare with the original resistance?

b) If the four are placed in parallel, how will the resistance of combination compare with the resistance of the original wire.

Q.

A wire of uniform cross-section and length l has a resistance of 4 ohms. The wire is cut into 4 equal pieces. Each piece is then stretched to length l. Thereafter, the four wires are joined in parallel. Calculate net resistance.

Q.

What is equivalent resistance

Q. A resistor has a resistance of 176 ohms . How many of these resistors should be connected in parallel so that their combination draws a current of 5 amperes from a 220volt supply line ?

Q. Materials that allow electric current to pass through them easily are known as _________ of electricity.

1. good conductors
2. semiconductors
3. bad conductors
4. insulators

Q.

Does lemon water have electrolytes?

Q.

A piece of wire of resistance 4 ohm is bent through 180° at its mid point and the two halves are twisted together, then find the resistance.

Q.

A parallel combination of 3 resistors takes a net current of 7.5A from a supply of 30 V. If 2 resistors are 10 ohm and 12 ohm.Find third resistor

Q. Materials that do not allow electric current to pass through them easily are known as _____________.

1. bad conductors
2. resistors
3. semiconductors
4. good conductors

Q. A 100V voltmeter of internal resistance 20kohm in series with a high resistance R is connected to 110V line.the voltmeter reads 5V , the value of R is A) 210 kohm B)315 kohm C) 420 kohm D) 4440 kohm

Q.

A resistor of 8 ohm disconnected in parallel with another resistor x. The resultant of the combination is 4.8 ohms. What is the value of resistor x

Q.

How many bulbs of 8 ohms should be joined in parallel to draw a current of 2A from a battery of 4V? Does this circuit obey Ohm's Law?

Q.

How to find the total resistance of an electric circuit if there is resistance R1 , R2, R3, R4, R5 individualaly.

Q.

How many 176 ohm resistors are required to carry 5A on 220V line

Q. Statement 1: Distilled water conducts electricity.
Statement 2: Tap water does not conduct electricity.
Which of the following is correct?

1. Statement 1 is true but statement 2 is false.
2. Statement 1 is false but statement 2 is true.
3. Both the statements are true.
4. Both the statements are false.

Q.

Give an example of a conductor.

Q.

Two resistors when in series have an effective resistance of 25 Ω & when in parallel have an effective resistance of 4 Ω. Calculate the value of individual resistances.

1. 2 Ω and 50 Ω

2. 20 Ω and 5 Ω

3. 15 Ω and 5 Ω

4. 20 Ω and 5 Ω

5. 15 Ω and 10 Ω

Q. How many resistors of 160 Ω should be connected in parallel to get 11 A current from a 220 V supply?

1. 
   3
2. 
   6
3. 
   4
4. 
   8

Q. Electric shocks can be prevented using __________.

1. rubber
2. iron
3. copper
4. silver

Q. Question 3
Let the resistance of an electrical component remains constant while the potential difference across the two ends of the component decreases to half of its former value. What change will occur in the current through it?

Q. The values of two resistors are 5.0+-0.2 k ohm and 10.0+-0.1 k ohm.what is the % error in the equivalent resistance when they are connected in parallel?

Q.

Calculate the equivalent resistance between A and B from the following diagram:

1. 10 Ω

2. 3 Ω

3. 45 Ω

4. 30Ω

Q.

Two conducting wires of the same material and of equal length and equal diameters are first connected in series and then parallel in a circuit across the same potential difference. The ratio of heat produced in series and parallel combinations would be-

(a) 1:2

(b) 2:1

(c) 1:4

(d) 4:1

Q.

A wire is cut into three equal parts and then connected in parallel with the same source .How will it's resistance and resistivity get affected

Q. Statement 1: Electrically conductive liquids do not allow electric current to pass through them.
Statement 2: Electrically conductive liquids allow the electric current to pass through them.
Which of the following is correct?

1. Statement 1 is false but statement 2 is true.
2. Both the statements are true.
3. Both the statements are false.
4. Statement 1 is true but statement 2 is false.

Q. In the given circuit current (I) will be .

1. 1.4 A
2. 2.4 A
3. 4 A

Q.

A uniform conducting wire offers a resistance of 60 Ω. It is cut into 12 equal parts and 6 of them are connected in parallel and remaining 6 are connected in series. This parallel bundle is connected in series with the series chain. Then, find the net resistance.

1. 30.84 Ω

2. 32.84 Ω

3. 29.84 Ω

4. 31.84 Ω

Q. An electrician comes to your house to fix a fan. He asks for a wooden stool to stand upon and uses rubber gloves while fixing the fan. Why do you think he does that?

1. Wooden stools are easily available. Rubber gloves protect against cuts.
2. Wooden stools are safe to stand on. Rubber gloves keep your hands clean.
3. Wooden stools are cheap to buy. Rubber gloves serve no purpose.
4. Wooden stools are good insulators. Rubber gloves are good insulators.

Q.

A resistor

has a resistance fo 176 ohms. How many of these resistors should be connected in parallel so that their combination draws a current of 5 amperes from a 220 volt supply line?

Q.
The bulb does not glow if the electrodes are immersed in __________ .

1. sodium chloride solution
2. sodium hydroxide solution
3. pure water
4. tap water