Physics MCQs for NEET — Practice Questions with Answers

The THERMODYNAMICS_Physics chapter states, 'Examples of state variables are pressure (P), volume (V), temperature (T), and mass (m). Heat and work are not state variables.'

The THERMAL_PROPERTIES_OF_MATTER chapter mentions, 'since PV = constant and V/T = constant for a given quantity of gas, then PV/T should also be a constant. This relationship is known as ideal gas law.' So, $\frac{PV}{T}$ is constant.

The KINETIC_THEORY chapter states, 'This is a fundamental result relating temperature, a macroscopic measurable parameter of a gas (a thermodynamic variable as it is called) to a molecular quantity, namely the average kinetic energy of a molecule. The two domains are connected by the Boltzmann constant.'

The THERMAL_PROPERTIES_OF_MATTER chapter states, 'Holding the volume of a gas constant, it gives P $\propto$ T. Thus, with a constant-volume gas thermometer, temperature is read in terms of pressure.'

The KINETIC_THEORY summary states, '$PV = \mu RT = k_B NT$ where N is the number of molecules. Since $N = \mu N_A$, then $R = k_B N_A$.

According to the NCERT text 'Thus, Gauss’s law for magnetism is: The net magnetic flux through any closed surface is zero.' This law reflects the non-existence of isolated magnetic poles (monopoles).

The NCERT text states: 'The difference between the Gauss’s law of magnetism and that for electrostatics is a reflection of the fact that isolated magnetic poles (also called monopoles) are not known to exist.' Since magnetic monopoles don't exist, magnetic field lines always form closed loops, implying no net flux through a closed surface. Electrostatic field lines originate from positive charges and end on negative charges.

Gauss's law for electrostatics states that $\oint \vec{E} \cdot d\vec{A} = q/\epsilon_0$, where $q$ is the enclosed electric charge. If magnetic monopoles existed, they would act as sources or sinks for magnetic field lines, similar to electric charges. Therefore, Gauss's law for magnetism would become $\oint \vec{B} \cdot d\vec{A} = \mu_0 q_m$, where $q_m$ is the enclosed magnetic monopole charge.

Magnetic field lines form closed loops, originate from the North pole and end at the South pole (outside the magnet, and continue inside from South to North), and do not intersect. Magnetic fields can pass through conductors; for example, a current-carrying wire produces a magnetic field in the surrounding space, including within the wire itself if considered.

The NCERT text explicitly states: 'Thus, Gauss’s law for magnetism is: The net magnetic flux through any closed surface is zero.' Mathematically, magnetic flux is given by the surface integral of the magnetic field, so $\oint \vec{B} \cdot d\vec{A} = 0$.