The air inside becomes warmer, and that makes it LESS DENSE.
Less-dense air FLOATS in denser air. Since it's inside the balloon, it picks the balloon up when it floats.
Answer and Explanation:
a. An oxygen-filled balloon is not able to float in the air, because the oxygen inside the balloon is of the same density, that is, the same "weight" as the oxygen outside the balloon and present in the atmosphere. The balloon can only float if the gas inside it is less dense than atmospheric oxygen. Helium gas is less dense than atmospheric gas, so if a balloon is filled with helium gas, that balloon will be able to float because of the difference in density.
b. The ship is able to float in the water because its steel construction is hollow and full of air. This makes the average density of this ship less than the density of water, which makes the ship lighter than water and for this reason, this ship is able to float. In addition, the ship is partially immersed, allowing the weight of the ship on the water to counteract the buoyant force that the water promotes on the ship. Weight and buoyant are two opposing forces that keep the ship afloat.
Explanation:
In the given question, the two metal spheres were hanged with the nylon thread.
When these two spheres were brought close together, they attracted each other. The attraction between these spheres is the result of the opposite charges between them.
The possible ways by which these two metal spheres can be charged are by induction that is touching the metal or by rubbing them.
During induction, the same charges are transferred to each sphere. In this case, either both the spheres will be negatively charged or positively charged.
It is not possible that after the sphere touch each other they will cling together because the same charge repels each other and during touching, if one sphere is neutral, then the charged one will transfer the same charge. And as we know that same charge repel each other therefore they will repel each other.
Explanation:
Half-life is the time taken for a radioactive material to decay to half its original composition:
Original mass = 48g
Half- life = 2hr
After four half lives;
Initially: 48g
First halving 24
Second halving 12
Third halving 6
Fourth halving 3
After second half life, we would have 12g
At fourth halving, we would have 3g
Answer:
37.725 A
Explanation:
B = magnitude of the magnetic field produced by the electric wire = 0.503 x 10⁻⁴ T
r = distance from the wire where the magnetic field is noted = 15 cm = 0.15 m
i = magnitude of current flowing through the wire = ?
Magnetic field by a long wire is given as

Inserting the values

i = 37.725 A