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A current of 250 mA flows through a circuit with a resistance of 12 ╬й. What is the potential difference across the circuit?
3.0 V
2.5 V
4.2 V
1.5 V
0 V
To calculate the potential difference, we apply Ohm's Law, which states that V=I├ЧR. Given the current I=250┬аmA=0.25┬аA and resistance R=12┬а╬й, the potential difference is 0.25┬аA├Ч12┬а╬й=3.0┬аV.
To calculate the potential difference, we apply Ohm's Law, which states that V=I├ЧR. Given the current I=250┬аmA=0.25┬аA and resistance R=12┬а╬й, the potential difference is 0.25┬аA├Ч12┬а╬й=3.0┬аV.
Think of voltage as the water pressure in a pipe, current as the flow of water, and resistance as the narrowing of the pipe; a higher pressure is needed to push the same amount of water through a narrower opening.
Remember 'VIR': V=I├ЧR (Voltage = Current ├Ч Resistance).
V=I├ЧR тАФ Ohm's Law formula for potential difference
1┬аA=1000┬аmA тАФ Unit conversion factor
Ohm's Law describes the linear relationship between voltage, current, and resistance in an ohmic conductor. As electrons flow through a conductor, they encounter opposition called resistance; the potential difference acts as the 'pressure' required to overcome this resistance to maintain the current flow.
Always convert milliamperes (mA) to amperes (A) before calculating for SI units.
Ohm's Law holds true only at a constant temperature for ohmic conductors.
Potential difference is measured in Volts (V), which is equivalent to Joule per Coulomb (J/C).
Simplifies calculation of circuit parameters.
Provides a fundamental basis for electrical engineering design.
Not applicable to non-ohmic devices like semiconductors or diodes where resistance changes with voltage.
Designing household electrical circuits.
Testing components in a multimeter.
Standard unit of Current is Ampere (A).
Option B (2.5 V) is incorrect due to calculation error (ignoring conversion from mA to A).
Option C (4.2 V) and D (1.5 V) are incorrect results derived from faulty arithmetic.
A is correct тАФ The potential difference is calculated as the product of current in amperes and resistance in ohms, resulting in 3.0 V.
In physics competitive exams, always check for unit prefixes like 'm' (milli), 'k' (kilo), or 'M' (mega) as they are the most common source of silly calculation errors.
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