In an L-R series circuit, Voltage across resistor: VR=240V Voltage across inductor: VL=180V We are asked to find the supply voltage V. Step 1: Relation between voltages in series L-R circuit In a series L-R circuit, the resistor voltage VR and the inductor voltage VL are 90∘ out of phase (since VR is in phase with current, and VL leads the current by 90∘ ). Hence, the total voltage is obtained by the vector sum: V=√VR2+VL2 Step 2: Substitute given values ‌V=√(240)2+(180)2 ‌V=√57600+32400=√90000=300V Final Answer: 300V Option A