Final answer:
The specific battery level at which to begin charging depends on the type of battery and manufacturer guidelines; it is not possible to determine from the question alone. The charge that flows through a circuit with 2.5 A current in 0.5 s is 1.25 C. The current through a 2.2-kiloohm resistor connected to a 1.5 V battery is 0.6818 mA.
Step-by-step explanation:
If any cell reading is below a certain percentage, the battery should be put on charge. However, without a specific context or standard, it is not possible to give a definitive answer to the battery charge level at which it should be charged, i.e., whether it should be 50%, 60%, 70%, or 80%. It varies based on the type of battery and the manufacturer's recommendation.
In regard to the questions provided as examples, when a battery is connected to a bulb and there is 2.5 A of current in the circuit, the amount of charge that will flow through the circuit in 0.5 s can be calculated using the formula Q = I * t. Therefore, the charge Q in coulombs (C) is:
Q = 2.5 A * 0.5 s = 1.25 C
So the correct answer is (c) 1.25 C.
For Ohm's Law calculation involving a 2.2-kiloohm resistor and a D cell battery (1.5 V), the current through the resistor is given by I = V/R where V is the voltage and R is the resistance. The current I would then be:
I = 1.5 V / 2200 Ω = 0.0006818 A, which can also be expressed as 0.6818 mA.