दो प्रतिरोधक, जिनमें से प्रत्येक का मान 1000 Ω है, 200 V DC स्रोत के समानांतर क्रम (parallel) में जुड़े हुए हैं। परिपथ में प्रवाहित होने वाली विद्युत धारा ________ A होगी।

A DC source supplies a voltage of 15 V to two series-connected resistors, one of which is 7.5 Ω and the other is an unknown resistor R. If the total circuit current is 1 A, determine the value of the unknown resistance R.

A resistor of 10 Ω is connected to a constant voltage source. When another resistor is connected in series with it, the current in the circuit becomes half of its initial value. Assuming the supply voltage remains unchanged, the resistance of the second resistor is _______.