A uniform rod of length l and mass m is free to rotate in a vertical plane about A. The rod initially in horizontal position is released. The initial angular acceleration of the rod is : (Moment of inertia of rod about A is \(\bigg(\frac{ml^2}{3}\bigg)\)
- \(\frac{3g}{2l}\)
- \(\frac{2l}{3g}\)
- \(\frac{3g}{2I^2}\)
- mg\(\big(\frac{l}{2}\big)\)
The Correct Option is A
Solution and Explanation
The formula for the torque on A (τ) = mg\(\big(\frac{l}{2}\big)\)
We are aware of that. τ =\(\big(\frac{ml^2}{2}\big)\times \alpha\) = \(\frac{(mgl)}{2}\)
\(\alpha\) =\(\frac{3g}{2l}\)
The appropriate answer is (A): \(\frac{3g}{2l}\)
Top Questions on Electric charges and fields
- Define electric flux through a surface. Give the significance of a Gaussian surface. A charge outside a Gaussian surface does not contribute to total electric flux through the surface. Why?
- CBSE CLASS XII - 2025
- Physics
- Electric charges and fields
- A small conducting sphere A of radius \( r \) charged to a potential \( V \), is enclosed by a spherical conducting shell B of radius \( R \). If A and B are connected by a thin wire, calculate the final potential on sphere A and shell B.
- CBSE CLASS XII - 2025
- Physics
- Electric charges and fields
- A small spherical shell \( S_1 \) has point charges \( q_1 = -3 \, \mu C \), \( q_2 = -2 \, \mu C \) and \( q_3 = 9 \, \mu C \) inside it. This shell is enclosed by another big spherical shell \( S_2 \). A point charge \( Q \) is placed in between the two surfaces \( S_1 \) and \( S_2 \). If the electric flux through the surface \( S_2 \) is four times the flux through surface \( S_1 \), find charge \( Q \).
- CBSE CLASS XII - 2025
- Physics
- Electric charges and fields
- What is the difference between an open surface and a closed surface?
- CBSE CLASS XII - 2025
- Physics
- Electric charges and fields
- Find the least distance from the central maximum where the bright fringes due to both the wavelengths coincide.
- CBSE CLASS XII - 2025
- Physics
- Electric charges and fields
Questions Asked in NEET exam
The current passing through the battery in the given circuit, is:
- NEET (UG) - 2025
- Current electricity
A bob of heavy mass \(m\) is suspended by a light string of length \(l\). The bob is given a horizontal velocity \(v_0\) as shown in figure. If the string gets slack at some point P making an angle \( \theta \) from the horizontal, the ratio of the speed \(v\) of the bob at point P to its initial speed \(v_0\) is :
- NEET (UG) - 2025
- Pendulums
- Two cities X and Y are connected by a regular bus service with a bus leaving in either direction every T min. A girl is driving scooty with a speed of 60 km/h in the direction X to Y. She notices that a bus goes past her every 30 minutes in the direction of her motion, and every 10 minutes in the opposite direction. Choose the correct option for the period T of the bus service and the speed (assumed constant) of the buses.
- NEET (UG) - 2025
- Relative Velocity
- The intensity of transmitted light when a polaroid sheet, placed between two crossed polaroids at \(22.5^\circ\) from the polarization axis of one of the polaroids (\(I_0\) is the intensity of polarised light after passing through the first polaroid):
- NEET (UG) - 2025
- Polarization
A full wave rectifier circuit with diodes (\(D_1\)) and (\(D_2\)) is shown in the figure. If input supply voltage \(V_{in} = 220 \sin(100 \pi t)\) volt, then at \(t = 15\) msec:
- NEET (UG) - 2025
- Semiconductor Diode
Concepts Used:
Electric charges and field
What is Electric Charge
It is the property of subatomic particles that experiences a force when put in an electric and magnetic field.
What is Electric Field
It is a property associated with each point in space when charge is present in any form. The magnitude and direction of the electric field are expressed by E, called electric field strength or electric field intensity.
Electric charges are of two types: Positive and Negative. It is commonly carried by charge carriers protons and electrons.
Properties of Electric Charge
Various properties of charge include the following :-
- Additivity of Electric Charge
- Conservation of Electric Charge
- Quantization of Electric Charge
Types of electric charge
Two kinds of electric charges are there :-
Negative Charge - When an object has a negative charge it means that it has more electrons than protons.
Positive Charge - When an object has a positive charge it means that it has more protons than electrons.
When there is an identical number of positive and negative charges, the negative and positive charges would cancel out each other and the object would become neutral.