Physics Questions

Land is considered as an important resource because it is useful in producing many things. For example, in agriculture, land is used for cultivating the crop, in industrial use, it is used for constructing factories and to make products that we use.

Aluminum has a resistivity varying from 2.65 to 2.82 × 10−8 Ω m.The resistivity of copper is generally given as: 1.72 x 10-8 Ω.m.So, since resistivity of aluminium is higher than that of copper, so Power dissipated will be greater than P. this is because rest of the factors (l, A and i) are constant.

Application of temperature changes in the atmosphere is in adiabatics, or temperature change which are caused by compressing or allowing air to expand.

No work done as there is no external external pressure in free expansion. 

Hence, Work done in a free expansion process is Zero.

Resistivity :

Resistivity is a measure of the resistance to the flow of electrons. 

Conductivity :

Conductivity is just the inverse of resistivity, σ = 1/ρ, where σ is conductivity and ρ is resistivity.

Example:

Think of a pipe and water, the bigger the pipe, the easier water can flow and thus the lower the resistance. 

Bicycle is a compound machine in the above given options. A compound machine is a machine that is formed by two or more simple machines.