A battery of emf 10 V and internal resistance 3 Ω is connected to a resistor. If the current in the circuit is 0.5 A, what is the resistance of the resistor? What is the terminal voltage of the battery when the circuit is closed?
A battery of emf 10 V and internal resistance 3 Ω is connected to a resistor. If the current in the circuit is 0.5 A, what is the resistance of the resistor? What is the terminal voltage of the battery when the circuit is closed?
Solution and Explanation
Emf of the battery, E = 10 V
Internal resistance of the battery, r = 3 Ω
Current in the circuit, I = 0.5 A
Resistance of the resistor = R
The relation for current using Ohm’s law is,
\(I = \frac{E}{R+r}\)
\(R+r = \frac{E}{I}\)
\(R+r = \frac{10}{0.5}\)
\(R+r = 20 Ω\)
\(∴ R = 20-3 = 17 Ω\)
Terminal voltage of the resistor = V
According to Ohm’s law,
\(V = IR\)
\(V = 0.5 × 17\)
\(V = 8.5 V\)
Therefore, the resistance of the resistor is 17 Ω and the terminal voltage is 8.5 V.
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Concepts Used:
EMF
EMF stands for electromagnetic field, which is a physical field produced by the movement of electrically charged particles. This field is composed of both electric and magnetic fields, which are perpendicular to each other and propagate through space as waves.
EMF is produced whenever an electrical current flows through a wire or other conductor. The strength of the EMF depends on the magnitude of the current and the frequency of the waves. High-frequency EMF waves are known as radio waves and are used for communication, while low-frequency EMF waves are used in power generation and transmission.
EMF has a wide range of applications in technology, such as in wireless communication, electrical power generation, and medical imaging. However, exposure to high levels of EMF has been linked to potential health risks, such as increased cancer risk, and there is ongoing research into the effects of EMF exposure on human health.
To measure EMF, specialized equipment such as EMF meters are used. These meters measure the strength and frequency of the electromagnetic waves in a given location. EMF shielding materials, such as conductive fabrics and metals, can also be used to reduce exposure to EMF.
Overall, EMF is an important physical phenomenon with many applications in technology, but it is also important to consider its potential health risks and take measures to reduce exposure when necessary.