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`IB DP Physics Questions`

Question 1

**A copper wire has a resistance of R at room temperature. If the temperature of the wire is increased, what will happen to its resistance?**

A. Remains the same

B. Decreases

C. Increases

D. Becomes zero

Question 2

**Which of the following materials has the highest resistivity at room temperature?**

A. Silver

B. Copper

C. Iron

D. Rubber

Question 3

**According to Ohm's law, if the voltage across a resistor is doubled, the current through it will:**

A. Remain the same

B. Be halved

C. Be doubled

D. Be quadrupled

Question 4

**A device consumes 60W of power when connected to a 240V supply. What is the resistance of the device?**

A. 960 ohms

B. 480 ohms

C. 240 ohms

D. 120 ohms

Question 5

**Which of the following is NOT a limitation of Ohm's law?**

A. It does not apply to non-linear devices.

B. It does not apply at very high frequencies.

C. It does not apply to superconductors.

D. It does not apply to resistors.

Question 6

**a)** Define Ohm's law and state its mathematical expression. [2]

**b)** A resistor has a constant voltage of 12 V applied across it and carries a current of 3 A. Calculate its resistance using Ohm's law. [3]

Question 7

**a) **Explain the concept of resistivity and how it differs from resistance. [3]

**b)** A copper wire has a length of 2 m, a cross-sectional area of 1 x 10^-6 m^2, and a resistance of 0.1 ohms. Calculate its resistivity. [2]

Question 8

**a)** Define electric power and state its relation to voltage and current. [2]

**b)** A device operates on a voltage of 230 V and draws a current of 5 A. Calculate the power consumed by the device. [3]

Question 9

**a) **Describe the relationship between current, resistance, and the heat produced in a resistor. [3]

**b)** A 10-ohm resistor has a current of 2 A flowing through it. Calculate the heat produced in the resistor in 5 seconds. [3]

**c) **How would the heat produced change if the current is doubled? [2]

Question 10

**a)** Define resistivity and state its unit. [2]

**b)** A material has a resistance of 8 ohms when its length is 2 m and its cross-sectional area is 2 x 10^-6 m^2. Calculate its resistivity. [3]

**c)** How would the resistance change if the length of the material is halved while keeping the cross-sectional area constant? [2]

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