Finding the resistance of unknown resistor R

Flemeng's Left Hand Rule, using your left hand, with the thumb, 1st finger and 2nd finger all 90 degrees to one another. This is covered in Electromagnetism. 1. Thumb represents the Force (F) – the direction the conductor (like a wire) will move. 2. First Finger (index finger) represents the Magnetic Field (B) – the direction of the magnetic field, from North to South. 3. Second Finger (middle finger) represents the Current (I) – the direction of conventional current flow (from positive to negative). So, if you arrange your left hand with your thumb, first finger, and second finger perpendicular to each other: Point your First Finger in the direction of the magnetic field. Point your Second Finger in the direction of the current. Your Thumb will point in the direction of the force, showing the movement of the conductor. This rule is particularly helpful in predicting the direction of force in a DC motor, where a current-carrying conductor is placed in a magnetic field.

Fleming's Right-Hand Rule is another useful rule for understanding electromagnetic induction. This rule helps us determine the direction of induced current when a conductor (such as a wire) moves within a magnetic field. It’s commonly applied in generators. Here’s how it works: 1. Thumb represents the Motion (or Force) – the direction in which the conductor is moving. 2. First Finger (index finger) represents the Magnetic Field (B) – the direction of the magnetic field from North to South. 3. Second Finger (middle finger) represents the Induced Current (I) – the direction of the induced current. To use Fleming's Right-Hand Rule, hold out your right hand with your thumb, first finger, and second finger all perpendicular to each other: Point your First Finger in the direction of the magnetic field. Point your Thumb in the direction of the conductor's movement. Your Second Finger will point in the direction of the induced current. This rule is very useful in understanding how generators work. When a conductor moves through a magnetic field, it experiences a change in magnetic flux, which induces a current in the conductor – the direction of which can be predicted with this rule.

2002PPQ38, 2003PPQ38, 2005PPQ37, 2006PPQ38, 2007PPQ39 Answer: Option B Answer: Option D Answer: Option B Answer: Option C Answer: Option B Answer: Option A Answer: Option C Answer: Option B Answer: Option D

2005SPQ20, 2006PPQ40, 2005PPQ38, 2003PPQ39 Answer: Option A Answer: Option D Answer: Option B Answer: Option C Answer: Option B Answer: Option B

Alpha particle is a helium nucleus which is positive charged . Beta particle is an electron which is negative charged . Gamma ray has no charge. Charged particle will be deflected by electric field by laws of electrostatic (like charges repel and unlike charges attract. Charged particle will be deflected by magnetic field and you can determine the direction using FLHR . (Note that beta is negative charge, it is like electron flow which is opposite to convectional current.) Watch the view to revise. Questions: 2007PPP1Q39, 2004PPP1Q37 Answer: Option D Answer: Option B Answer: Option B Answer: Option A Answer: Option D

Half-life of a radioactive nuclide is the time taken for half the nuclei of that nuclide in any sample to decay . (time taken for the count rate/mass/nuclei/atoms to fall to half of its original value) Quick revision on half-life. 2002SPP1Q19, 2003SPP1Q19, 2006SPP1Q20, 2004SPp1Q19 Questions: Answer: Option C Answer: Option C Answer: Option C Answer: Option C Answer: Option D Answer: Option C Answer: Option C Answer: Option B Answer: Option D Answer: Option D