Answer: Option D Note that the reading shown on the detector (536 counts per second) includes the sum of count rate from the...

Answer: Option B We usually encounter decay graph of the unstable radiaoactive substance. But this graph is the mass-time graph of the...

Answer: Option D We always use FLHR to find the force on the wire. But magnetic forces is a action-reaction pair. So when the force...

Answer: Option C This is a heating curve. So the specific latent heat of fusion here refers to the melting process, which occurs from...

Answer: Option A The direction of the magnetic field is downwards in the diagram. You can think of a North Pole of a magnet that is at...

Answer: Option D Refer to the video for the explanation

Answer: Option A For such questions, always locate accurately the position of the image of the O. Then draw the ray from the image to the...

Answer: Option D The most common mistake is to equate total energy at X equals to total energy at Y. At Y, there is no way to know the...

Answer: Option B To solve this question, you need to apply your FLHR. From the image, you will be able to know the orientation of the...

Answer: Option A Once the water wave is produced, frequency of the wave remains constant even when it travels from deep to shallow or...

Answer: Option B Refer to the video explanation

Answer: Option D For total internal reflection TIR to occur, two conditions must be present: 1. light must be travelling from a optically...

Answer: Option B Using conservation of energy (COE), the total energy of the car at X = total energy at Y. At X, the car only has...

Answer: Option A Refer to the video explanation

Answer: Option A Firstly, you need to know that at both pivot P and Q, there are normal contact forces acting upwards on the plank. 2...

Answer: Option C For such questions, always look at the blocks as one single system and find the acceleration of the whole as one. That...

Answer: Option D Alpha emission is the least penetrating, easily be blocked by a few cm of air, skin or thin paper. Beta emission can be...

Answer: Option C With first glance, we may think of using kinematics to solve. It can, but the process will be longer. Refer to the...

Answer: Option B Emf is the work done (energy needed) to carry a unit charge (1C) through the whole complete circuit. By definition, it...

Answer: Option B Wavefront is an imaginary line that joins all identical adjacent points that are in phase. So if you assume the circular...