FreeNotes
When the distance between the plates of a capacitor increases, the capacitance decreases because capacitance is inversely proportional to the distance between the plates. The formula for capacitance is: C=ε0⋅A/d Where: C is the capacitance, ε0 is the permittivity of free space, A is the area of the plates, d is the distance between the … Read more
A pointed tip helps in the easy discharge of electric charge into the air due to the concentration of charge at the sharp end. This prevents the buildup of large charges, reducing the chances of a lightning strike on the building. Related Questions: Two parallel straight conductors carrying current in the same direction attract each … Read more
Walking on a carpet causes friction, which transfers electrons to or from the body, creating static charge buildup. When the person touches a metal object (a conductor), the charge quickly discharges, causing a small electric shock. Related Questions: Two parallel straight conductors carrying current in the same direction attract each other? Explain why. What will … Read more
When a charged balloon is brought near a neutral wall, it induces an opposite charge on the surface of the wall. Since opposite charges attract, the balloon sticks to the wall due to electrostatic attraction. Related Questions: Two parallel straight conductors carrying current in the same direction attract each other? Explain why. What will you … Read more
Split rings (commutators) in a DC motor: They reverse the direction of current every half rotation to ensure continuous rotation in one direction. Slip rings in an AC motor: They do not reverse the current, allowing the coil to receive alternating current (AC) continuously, making the motor rotate smoothly in both directions. Related Questions: Two … Read more
According to Lenz’s Law, the induced current in the coil opposes the motion of the magnet. When the coil has more turns, the induced emf and current increase, producing a stronger opposing magnetic field. This results in a greater opposing force felt on your hand. Related Questions: Two parallel straight conductors carrying current in the … Read more
Step-up transmission is used for long distances because increasing voltage reduces current (as per P = VI). Since power loss (P = I²R) is directly proportional to current squared, reducing current minimizes heat loss in transmission lines, making electricity transmission more efficient over long distances. Related Questions: Two parallel straight conductors carrying current in the … Read more
The coils of a transformer are wound on an iron core to increase magnetic flux linkage between the primary and secondary coils. Iron is a good conductor of magnetic fields, so it helps concentrate and guide the magnetic field efficiently, reducing energy losses and increasing the efficiency of the transformer. Related Questions: Two parallel straight … Read more
A transformer works on the principle of electromagnetic induction, which requires a changing magnetic field to induce voltage in the secondary coil. When DC voltage is applied, the current remains constant, producing a steady magnetic field instead of a changing one. Since no electromagnetic induction occurs, no voltage is induced in the secondary coil, resulting … Read more
(a) The magnet is moving towards the ring According to Lenz’s Law, the ring will oppose the motion of the magnet by creating an induced current that produces a north pole on the side facing the approaching magnet. The induced current in the ring will be anticlockwise when viewed from above. (b) The magnet is … Read more