Magnetic Effects of Electric Current Class 10 Notes PDF

CLASS 10 NOTES SCIENCE Magnetic Effects of Electric Current PRASHANT KIRAD  PRASHANT KIRAD Hans Christian Oersted found that if you put a compass next to a wire with an electric current flowing through it,...

CLASS 10 NOTES SCIENCE Magnetic Effects of Electric Current PRASHANT KIRAD  PRASHANT KIRAD Hans Christian Oersted found that if you put a compass next to a wire with an electric current flowing through it, the needle in the compass would move. He thought this happened because the electric current created a magnetic field, which caused the compass needle to deflect. Magnetic fields: The region around a magnet where a magnetic force is felt is called the magnetic field. It's a vector quantity, and its unit in the International System of Units (SI) is the tesla. EMA Magnetic field Lines: Imaginary lines that depict the magnetic field are observed when iron fillings are placed near a D magnet, forming a pattern that illustrates the RA arrangement of magnetic field lines. Magnetic field lines start at the North pole of a magnet KI and extend to the South pole outside the magnet. However T within the magnet, the direction is from South to North. AN They create unbroken, closed curves. The tangent indicates the direction of the magnetic field at any point on the magnetic field lines. JOSH METER? H Magnetic field lines never intersect each other. AS When magnetic field lines are closely spaced, the magnetic field is stronger. Conversely, the magnetic field is weaker if the field lines are spaced farther apart. PR The magnetic field is produced by a current flowing through a straight conductor. Magnetic field lines form concentric circles with the center at the wire. The strength of the magnetic field increases with an increase in current. The strength of the magnetic field decreases as we move away from the wire. Maxwell's Right-Hand thumb Rule: Maxwell's Right-Hand Thumb Rule helps you find the direction of the magnetic field around a wire with current. Point your thumb in the direction of the current, and the way your fingers curl shows the magnetic field's direction.  PRASHANT KIRAD Magnetic field due to a current circular Loop: When current flows through a circular loop: 1. Inside the loop, the magnetic field runs along the axis. 2. Outside the loop, it forms concentric circles. 3. The field's strength depends on the current and loop size. 4. The direction inside is determined by the current using the right-hand rule. Magnetic field due to current in a solenoid: EMA 1. Magnetic field lines run through the core. 2. It resembles the magnetic field around a bar magnet. 3. Strength depends on current and the number of turns in the solenoid. 4. The field's direction is determined by the right-hand rule. Electromagnet: D An electromagnet is a temporary magnet created by passing RA an electric current through a coil of wire. It exhibits magnetic properties only when the current flows, making it KI useful in various applications like doorbells and electric locks. The strength of the electromagnet can be adjusted by T changing the current or the number of coils in the wire. AN Force on a current-carrying conductor in a magnetic field: H When a current-carrying conductor is placed in a magnetic field: AS 1. It experiences a force perpendicular to both the current direction and the magnetic field direction. 2. The force's strength increases with the amount of current and the strength of the PR magnetic field. 3. The direction of the force is determined by Fleming's Left-Hand Rule, where the thumb represents motion, the forefinger indicates magnetic field, and the middle finger denotes current direction. Fleming's Left Hand rule: Fleming's Left-Hand Rule is a way to figure out the direction of three things: the magnetic field (fore finger), the current (middle finger), and the force or motion (thumb). Imagine holding your left hand with your thumb, fore finger, and middle finger at right angles to each other. If you point your fore finger in the direction of the magnetic field, and the middle finger in the direction of the current, then your thumb will point in the direction of the force or motion. It helps to remember how these three things are related in a magnetic field.  PRASHANT KIRAD Galvanometer: A device capable of sensing the presence of an electric current in a circuit. The needle stays at the zero position (center of the scale) when there is no current. Depending on the current direction, the pointer can shift to either the left or right of the zero mark on the scale. Types of Current DC (Direct Current) AC (Alternating Current) It is the electric current which It is the electric current which reverses its D flows in the same direction. direction after every fixed interval of time Domestic Circuit: RA KI Electricity generated at power stations is conveyed to our homes through two robust copper or aluminum wires. T One of these wires is known as the live wire, distinguished AN by its red insulation cover, and it operates at a voltage of “” 220 V with a frequency of 50 Hz. - Prashant Bhaiya H The other is termed the neutral wire, identifiable by its AS black insulation cover, and it is at zero potential. The live and neutral wires enter an electricity meter, commonly installed in homes, PR through a primary fuse. They are linked to the line wires in the home through a primary switch. Each distribution circuit is equipped with an individual fuse. In the event of a fault, such as a short circuit in one circuit, its respective fuse blows, while the other circuit remains unaffected. All electric appliances, such as bulbs and fans, are connected in parallel across the live wire and neutral wire.  PRASHANT KIRAD The electric supply reaching our homes has two wires: Live Wire (Phase Wire): Typically colored red or brown, it carries the current from the power source to the electrical appliances. Neutral Wire: Usually blue or black, it completes the circuit by providing a return path for the current to flow back to the power source. Earth Wire: The earth wire, often green or bare, is a safety wire in electrical circuits. It provides a path for excess electrical Neutral Live Earth current to safely flow into the ground, preventing electric shocks and ensuring safety in case of faults. Fuse: D A safety device made of a thin wire composed of a tin and RA lead alloy with a low melting point. Its purpose is to prevent potential damage caused by overloading and short-circuiting. KI T AN H AS PR  PRASHANT KIRAD # TOP 7 IMPORTANT QUESTIONS 1) What are permanent magnets and electromagnets? Give two uses of each. [CBSE 2010] Solution: Permanent Magnet: It has a constant magnetic field around it. e.g. generator, loudspeaker. Electromagnet: When a soft iron is placed in a solenoid it gets magnetized till there is current in the solenoid, e.g. electric bells, or cranes. 2) Differentiate overloading and short-circuiting. (CBSE 2010) Solution: D Overloading means to draw current more than the permitted maximum current in the RA circuit which may be due to connecting many appliances in one socket. In short, circuiting, when live wire and neutral wire come in contact with each other then the KI resistance of the circuit becomes minimal consequently the current in the circuit increases abruptly. It may be due to damage to the insulation of the wire. T AN 3) What happens to the deflection of the compass needle placed at a point near the current carrying a straight conductor: (CBSE 2011, 2014) a. if the current is increased? H b. if the direction of current in the conductor is changed (reversed)? AS c. if the compass is moved away from the conductor? Solution: PR a. If the current increases deflection of the compass increases. b. If the direction of current is reversed the deflection in the compass needle is also reversed. c. The deflection of the compass needle decreases when a compass is moved away from the conductor. 4) (a) Which effect of the electric current is utilized in the working of an electrical fuse? (b) A fuse is connected in series or parallel in a household circuit? (c) Draw a schematic labeled diagram of a domestic circuit that has a provision of a main fuse, meter, one light bulb, and a switch socket. Solution: a. Heating effect of current b. In series in the household circuit  PRASHANT KIRAD c. 5) State one main difference between A.C. and D.C. Why AC is preferred over D.C. for long-range transmission of electric power ? Name one source for each of A.C. and D.C. (CBSE 2012) Solution: The magnitude and direction of D.C. remain the same whereas A.C. changes its magnitude and direction periodically. Low AC voltage can be increased to high voltage to prevent loss of electric energy during its long-distance transmission. A.C. generator and D.C. generator/or cell. D 6) (a) Mention the color code used for live, neutral, and earth wire. (b) You want to connect a 2 kW electric oven to the electric circuit. In which power RA line would you connect it and why? What may happen if you connect it wrongly to the other power line? KI Solution: T (a) Live wire – Red, Neutral wire – Black & Earth wire – Green AN (b) 2 kW electric iron draws a large current. If it is connected to a socket of 5A then the fuse will be blown. So it is connected to the power socket of 15 A H 7) (a) State the function of a fuse in an electric circuit. How is it connected in the AS domestic circuit? (b) An electric fuse of rating 3A is connected in a circuit in which an electric iron of PR power 1.5 kilo watt is connected which operates at 220 V. What would happen? Explain. Solution: (a) Fuse is a safety device to prevent damage to electrical devices from short circuits or overloading. A fuse is connected in series with the circuit. “Class 10th Phodenge”