List of top Physics Questions asked in JEE Main

An object of mass 5 kg is thrown vertically upwards from the ground. The air resistance produces a constant retarding force of 10 N throughout the motion. The ratio of time of ascent to the time of descent will be equal to [Use \(g\) = \(10 \;ms^{–2}\)].
Two cells of same emf but different internal resistances r1 and r2 are connected in series with a resistance R. The value of resistance R, for which the potential difference across second cell is zero, is
If n represents the actual number of deflections in a converted galvanometer of resistance G and shunt resistance S. Then the total current I when its figure of merit is K will be

A transistor is used in common-emitter mode in an amplifier circuit. When a signal of 10 mV is added to the base-emitter voltage, the base current changes by 10 mA and the collector current changes by 1.5 mA. The load resistance is 5 kW. The voltage gain of the transistor will be ___.

A \(72\) Ω galvanometer is shunted by a resistance of \(8\) Ω. The percentage of the total current which passes through the galvanometer is
Resistance of the wire is measured as 2 Ω and 3 Ω at 10°C and 30°C respectively. Temperature co-efficient of resistance of the material of the wire is:
The length of a given cylindrical wire is increased to double of its original length. The percentage increase in the resistance of the wire will be ______%.

In a series LCR circuit, the inductance, capacitance and resistance are L = 100 mH, C = 100 μF and R = 10 Ω respectively. They are connected to an AC source of voltage 220 V and frequency of 50 Hz. The approximate value of current in the circuit will be ______ A.

AC source of voltage 220 V and frequency of 50 Hz

In an experiment of CE configuration of n–p–n transistor, the transfer characteristics are observed as given in figure. 

In an experiment of CE configuration of n–p–n transistor

If the input resistance is 200 Ω and output resistance is 60 Ω, the voltage gain in this experiment will be______.

A potentiometer wire of length 10 m and resistance 20 Ω is connected in series with a 25 V battery and an external resistance 30 Ω. A cell of emf E in secondary circuit is balanced by 250 cm long potentiometer wire. The value of E (in volt) is \(\frac {x}{10}\). The value of \(x\) is ______.
A 220 V, 50 Hz AC source is connected to a 25 V, 5 W lamp and an additional resistance R in series (as shown in figure) to run the lamp at its peak brightness, then the value of R (in ohm) will be _____ .
A 220 V, 50 Hz AC source is connected to a 25 V, 5 W lamp and an additional resistance R in series
A cell, shunted by a 8 Ω resistance, is balanced across a potentiometer wire of length 3 m. The balancing length is 2 m when the cell is shunted by 4 Ω resistance. The value of internal resistance of the cell will be _____ Ω.
The current density in a cylindrical wire of radius 4 mm is \(4×10^6\ Am^{–2}\). The current through the outer portion of the wire between radial distances \(\frac R2\) and \(R\) is _____ \(\pi\) A.
In the given circuit ‘a‘ is an arbitrary constant. The value of m for which the equivalent circuit resistance is minimum, will be \(\frac{\sqrt x}{2}\).The value of x is________.
The cut-off voltage of the diodes (shown in figure) in forward bias is \(0.6\; V\). The current through the resistor of \(40\) \(Ω\) is____ mA.
The cut-off voltage of the diodes
An aluminium wire is stretched to make its length, 0.4% larger. The percentage change in resistance is
All resistances in figure are 1 Ω each. The value of current ‘I‘ is \((\frac{a}{5})\) A. The value of a is _______.
value of current
In a coil of resistance \(8Ω\), the magnetic flux due to an external magnetic field varies with time as \(Φ=\frac{2}{3}(9−t^2)\).The value of total heat produced in the coil, till the flux becomes zero, will be _ \(J\).
A potentiometer wire of length 300 cm is connected in series with a resistance 780 Ω and a standard cell of emf 4V. A constant current flows through potentiometer wire. The length of the null point for cell of emf20 mV is found to be 60 cm. The resistance of the potentiometer wire is _____ Ω.
A potentiometer wire of length 300 cm is connected in series with a resistance 780 Ω and a standard cell of emf 4V
Resistance of the wire is measured as 2 Ω and 3 Ω at 10°C and 30°C respectively. Temperature co-efficient of resistance of the material of the wire is:
The dimensions of $\left(\frac{ B ^2}{\mu_0}\right)$ will be :(if $\mu_0$ : permeability of free space andB : magnetic field)
A charge particle is moving in a uniform magnetic field $(2 \hat{ i }+3 \hat{ j }) T$ If it has an acceleration of $(\alpha \hat{i}-4 \hat{j}) m / s ^2$, then the value of $\alpha$ will be
A teacher in his physics laboratory allotted an experiment to determine the resistance (G) of a galvanometer. Students took the observations for \(\frac 13\) deflection in the galvanometer. Which of the below is true for measuring value of G?
A bar magnetic having a magnetic moment of 2.0 × 105 JT–1, is placed along the direction of uniform magnetic field of magnitude B = 14 × 10–5 T. The work done in rotating the magnet slowly through 60° from the direction of field is:
A charge particle is moving in a uniform field \((2\hat i+3\hat j)T\). If it has an acceleration of \((α\hat i−4\hat j)\ m/s^2\), then the value of α will be