You obtain a 100 W light bulb and a 50 W light bulb. Instead of connecting them in the normal way, you devise a circuit that places them in series across normal household voltage. Which bulb glows more brightly?

Respuesta :

Answer:

50W bulb

Explanation:

Considering the relationship between power, resistance and voltage, we know that

[tex]R=\frac {v^{2}}{p}[/tex]

Where R is resistance, V is voltage across the circuit and P is power

Considering 100 W power, its resistance will be

[tex]R_{100}=\frac {v^{2}}{100}[/tex]

Similarly, resistance of a 50 W power will be

[tex]R_{50}=\frac {v^{2}}{50}[/tex]

Clearly, the resistance of 50W is greater than resistance of 100W

For series connection, power will be given by

P=I²R

For 100W bulb, power will be

[tex]P_{100}=I^{2}\frac {v^{2}}{100}[/tex]

For 50W bulb, power will be

[tex]P_{50}=I^{2}\frac {v^{2}}{50}[/tex]

The current will be the same hence it is clear that power of 50W bulb will be more than power of 100W bulb. Therefore, the 50W bulb has more brightness.