A 20 Ω resistor with temperature coefficient 0.04/°C is connected to a 24 V supply. If its temperature rises from 1.5°C to 10°C, determine: I) New resistance II) Circuit current before and after heating III) explain your answers.

here's the solution for Q4.a: Given: Initial resistance R_0 = 20 \, Temperature coefficient = 0.04 /^ C Initial temperature T_0 = 1.5^ C Final temperature T = 10^ C Supply voltage V = 24 \, V I) New resistance Step 1: Calculate the change in temperature. T = T - T_0 T = 10^ C - 1.5^ C T = 8.5^ C Step 2: Calculate the new resistance. The formula for resistance change with temperature is R = R_0 [1 + T]. R = 20 \, [1 + (0.04 /^ C) (8.5^ C)] R = 20 \, [1 + 0.34] R = 20 \, [1.34] R = 26.8 \, The new resistance is 26.8 . II) Circuit current before and after heating Step 3: Calculate the circuit current before heating. Using Ohm's Law, I_initial = (V)/(R_0). I_initial = (24 \, V)/(20 \, ) I_initial = 1.2 \, A The current before heating is 1.2 A. Step 4: Calculate the circuit current after heating. Using Ohm's Law, I_final = (V)/(R). I_final = (24 \, V)/(26.8 \, ) I_final ≈ 0.8955 \, A The current after heating is 0.8955 A. III) Explain your answers Step 5: Explain the change in current. As the temperature of the resistor increases from 1.5^ C to 10^ C, its resistance increases from 20 \, to 26.8 \, . According to Ohm's Law (I = V/R), for a constant voltage, an increase in resistance leads to a decrease in current. Therefore, the current in the circuit decreases from 1.2 \, A to approximately 0.8955 \, A. Drop the next question!