Effects of Electric Current — Maharashtra (SSC) Class 10 Science Solutions (Free)

Electric current is the flow of electric charge per unit time. Unit: Ampere (A). Current = charge/time = Q/t. Ohm's law: V = IR, where V is potential difference, I is current, R is resistance. At constant temperature, current through conductor is directly proportional to applied potential difference. Limitations: Does not apply to non-ohmic conductors (semiconductors, gases at low pressure), at very high temperatures, or to some nonlinear devices like diodes and transistors.

Step 1: Given R = 10 ohm, I = 2 A Step 2: Use Ohm's law: V = IR Step 3: V = 2 x 10 = 20 V Answer: Potential difference is 20 V. This means 20 joules of energy is given to each coulomb of charge passing through the wire.

Heating effect: When current flows through a conductor, it generates heat due to friction between moving electrons and atoms. Formula: Heat = I2Rt (Joule's law of heating). Factors: (1) Current (I): Heat is proportional to square of current, (2) Resistance (R): Heat is directly proportional to resistance, (3) Time (t): Heat is proportional to time of flow. Higher current, higher resistance, or longer duration produces more heat. Used in heaters, bulbs, electric stoves.

Step 1: Given I = 5 A, R = 20 ohm, t = 10 s Step 2: Use Joule's law: H = I2Rt Step 3: H = (5)2 x 20 x 10 Step 4: H = 25 x 20 x 10 = 5000 J Answer: Heat produced is 5000 joules or 5 kJ. This heat warms the conductor and surroundings.

Magnetic effect: When current flows through a conductor, a magnetic field is produced around it. Direction: Given by right-hand rule (thumb in current direction, fingers curl in field direction). Strength increases with current. Uses: (1) Electromagnets in electric bells, door locks, relays, (2) Magnetic field in electric motors, (3) Solenoids in switches. Current-carrying coil acts like a magnet. Strength can be controlled by changing current.