Explanation:
Iron has tiny magnetic domains inside it. Each domain acts like a tiny magnet with its own magnetic field. These domains are randomly distributed thus resulting in zero magnetic field and iron doesn't behave like a magnet.
When a copper wire is wound around the nail and current is passed through the coil, magnetic field is generated. This magnetic field penetrates through the nail. Due to this the magnetic domains of the nail align in the same direction thus having a net magnetic field. The nail behaves like a magnet till the time current flows through the coil.
Only ' A ' is always true.<em> (choice-1)</em>
' B ' is not true when you drop a red hot spoon into cold soup.
' C ' is not true when you drop a red hot marble into a cool swimming pool.
Answer: Yes and no.
Explanation: Mass is the amount of matter in an object, whereas weight is the force exerted on an object by gravity. Objects on the surface of the earth have weight, although sometimes the weight is difficult to measure.
I mean i guess its the metric system?
Heat released from combustion is calculated by multiplying the amount of substance being burned with its heat of combustion. From this, we can calculate the mass needed from the system above. The calculation is as follows:
-543 kJ = x x -1320 kJ/mol
x = 0.411 mol
Mass of x = 0.411 x 71.83 g/mol
Mass of x = 29.55 g
