List of top Physics Questions asked in JEE Main

In the given circuit diagram, the currents, $I_1 = 0.3\,A, I_4 = 0.8\, A$ and $I_5 = 0.4\, A$, are flowing as shown. The currents $I_2,I_3$ and $I_6$,respectively, are :

In the given circuit the cells have zero internal resistance. The currents (in Amperes) passing through resistance $R_1$, and $R_2$ respectively, are:

The Wheatstone bridge shown in Fig. here, gets balanced when the carbon resistor used as $R_1$ has the colour code ( Orange, Red, Brown). The resistors $R_2$ and $R_4$ are $80\Omega $ and $40 \Omega $ respectively. Assuming that the colour code for the carbon resistors gives their accurate values, the colour code for the carbon resistor, used as $R_3$, would be :

When the switch $S$, in the circuit shown, is closed, then the value of current $i$ will be :

The resistance of the meter bridge $AB$ is given figure is $4\Omega$ . With a cell of emf $\varepsilon = 0.5 \;V $ and rheostat resistance $R_h = 2 \; \Omega$ the null point is obtained at some point $J$. When the cell is replaced by another one of emf $\varepsilon = \varepsilon_2$ the same null point $J$ is found for $R_h = 6 \; \Omega$. The emf $\varepsilon_2$ is;

In the circuit shown, a four-wire potentiometer is made of a $400\, cm$ long wire, which extends between $A$ and $B$. The resistance per unit length of the potentiometer wire is $r = 0.01 $ $\Omega/cm$. If an ideal voltmeter is connected as shown with jockey $J$ at $50\, cm$ from end $A$, the expected reading of the voltmeter will be :

A cell of internal resistance r drives current through an external resistance $R$. The power delivered by the cell to the external resistance will be maximum when

A $2\, W$ carbon resistor is color coded with green, black, red and brown respectively. The maximum current which can be passed through this resistor is :

An electric dipole is formed by two equal and opposite charges $q$ with separation $d$. The charges have same mass $m$. It is kept in a uniform electric field $E$. If it is slightly rotated from its equilibrium orientation, then its angular frequency $\omega$ is :

Consider the $LR$ circuit shown in the figure. If the switch $S$ is closed at $t = 0$ then the amount of charge that passes through the battery between $t = 0$ and $t = \frac{L}{R}$ is:

At some location on earth the horizontal component of earth's magnetic field is $18 \times 10^{-6}$ T. At this location, magnetic needle of length $0.12\, m$ and pole strength $1.8\, Am$ is suspended from its mid-point using a thread, it makes $45^{\circ}$ angle with horizontal in equilibrium. To keep this needle horizontal, the vertical force that should be applied at one of its ends is :

A common emitter amplifier circuit, built using an npn transistor, is shown in the figure. Its dc current gain is $250, \,R_C = 1k\Omega$ and $V_{CC} = 10 V$. What is the minimum base current for $V_{CE}$ to reach saturation ?

A concave mirror has radius of curvature of $40\, cm$. It is at the bottom of a glass that has water filled up to $5\, cm$ (see figure). If a small particle is floating on the surface of water, its image as seen, from directly above the glass, is at a distance d from the surface of water. The value of d is close to : (Refractive index of water $= 1.33$)

A convex lens is put $10 \,cm$ from a light source and it makes a sharp image on a screen, kept $10\, cm$ from the lens. Now a glass block (refractive index $1.5$) of $1.5\, cm$ thickness is placed in contact with the light source. To get the sharp image again, the screen is shifted by a distance $d$. Then $d$ is :

A convex lens (of focal length $20\, cm$) and a concave mirror, having their principal axes along the same lines, are kept $80 \,cm$ apart from each other. The concave mirror is to the right of the convex lens. When an object is kept at a distance of $30\, cm$ to the left of the convex lens, its image remains at the same position even if the concave mirror is removed. The maximum distance of the object for which this concave mirror, by itself would produce a virtual image would be :

A gas can be taken from $A$ to $B$ via two different processes $ACB$ and $ADB$. When path $ACB$ is used $60\, J$ of heat flows into the system and $30\, J$ of work is done by the system. If path $ADB$ is used work done by the system is $10\, J$. The heat Flow into the system in path $ADB$ is :

A rigid diatomic ideal gas undergoes an adiabatic process at room temperature,. The relation between temperature and volume of this process is $TV^x$ = constant, then $x$ is :

A sample of an ideal gas is taken through the cyclic process abca as shown in the figure. The change in the internal energy of the gas along the path ca is $-180\,J$. The gas absorbs $250\, J$ of heat along the path ab and $60\, J$ along the path $bc$. The work done by the gas along the path $abc$ is :

A thermally insulated vessel contains $150\,g$ of water at $0^{\circ}C$. Then the air from the vessel is pumped out adiabatically. A fraction of water turns into ice and the rest evaporates at $0^{\circ}C$ itself. The mass of evaporated water will be closest to : (Latent heat of vaporization of water $= 2.10 \times 10^6 \; J \; kg^{-1}$ and Latent heat of Fusion of water = $3.36 \times 10^5 \; J \; kg^{-1}$)

For the given cyclic process $CAB$ as shown for a gas, the work done is :

Half mole of an ideal monoatomic gas is heated at constant pressure of 1 atm from $20{^{\circ}C}$ to $90^{\circ}C$. Work done by gas is close to : ( Gas constant R = $8.31\, J\, /mol-K$)

Surface of certain metal is first illuminated with light of wavelength $\lambda_1 =350 \; nm$ and then, by light of wavelength $\lambda_2=54\, \; nm$. It is found that the maximum speed of the photo electrons in the two cases differ by a factor of $2$. The work function of the metal (in eV) is close to : (Energjr of photon = $\frac{1240}{\lambda (in \; nm)} eV$)

In a radioactive decay chain, the initial nucleus is $^{232}_{90}Th$ . At the end there are $6 \alpha$-particles and $4 \beta$-particles which are emitted. If the end nucleus, If $^{A}_{Z} X$ , $A$ and $Z$ are given by :

A hydrogen atom, initially in the ground state is excited by absorbing a photon of wavelength 980$\mathring A $. The radius of the atom in the excited state, it terms of Bohr radius $a_0$, will be : ($h_c$ = $12500\, eV - \mathring A $)

Three particles of masses $50\, g, 100\, g$ and $150\, g$ are placed at the vertices of an equilateral triangle of side $1\, m$ (as shown in the figure). The $(x, y)$ coordinates of the centre of mass will be :