The intensity of the light from a bulb incident on a surface is 0.22 W/m2. The amplitude of the magnetic field in this light-wave is ___ × 10–9 T.
(Given : Permittivity of vacuum ε0 = 8.85 × 10–12C2N–1–m–2, speed of light in vacuum c = 3 × 108 ms–1)
The intensity of the light from a bulb incident on a surface is 0.22 W/m2. The amplitude of the magnetic field in this light-wave is ___ × 10–9 T.
(Given : Permittivity of vacuum ε0 = 8.85 × 10–12C2N–1–m–2, speed of light in vacuum c = 3 × 108 ms–1)
Correct Answer: 43
Solution and Explanation
The correct answer is: 43
\(I=\frac{1}{2}ε_oE_0^2.c=\frac{1}{2}ε_0(cB_0)^2\)
\(⇒B_0≃43×10-T\)
Top Questions on Surface tension
- A spherical air bubble is formed inside a liquid (like water). The radius of the bubble is 0.5 mm, and the surface tension of the liquid is 0.072 N/m. What is the pressure inside the bubble relative to the outside pressure?
- MHT CET - 2025
- Physics
- Surface tension
- Two water drops each of radius \( r \) coalesce to form a bigger drop. If \( T \) is the surface tension, the surface energy released in this process is:
- JEE Main - 2025
- Physics
- Surface tension
- An air bubble of radius 0.1 cm lies at a depth of 20 cm below the free surface of a liquid of density 1000 kg/m\(^3\). If the pressure inside the bubble is 2100 N/m\(^2\) greater than the atmospheric pressure, then the surface tension of the liquid in SI units is (use \(g = 10 \, {m/s}^2\)).
- JEE Main - 2025
- Physics
- Surface tension
Two soap bubbles of radius 2 cm and 4 cm, respectively, are in contact with each other. The radius of curvature of the common surface, in cm, is _______________.
- JEE Main - 2025
- Physics
- Surface tension
- An air bubble of radius 1.0 mm is observed at a depth of 20 cm below the free surface of a liquid having surface tension \( 0.095 \, \text{J/m}^2 \) and density \( 10^3 \, \text{kg/m}^3 \). The difference between pressure inside the bubble and atmospheric pressure is: Given \( g = 10 \, \text{m/s}^2 \).
- JEE Main - 2025
- Physics
- Surface tension
Questions Asked in JEE Main exam
If $10 \sin^4 \theta + 15 \cos^4 \theta = 6$, then the value of $\frac{27 \csc^6 \theta + 8 \sec^6 \theta}{16 \sec^8 \theta}$ is:
- JEE Main - 2025
- Trigonometric Identities
If the area of the region $\{ (x, y) : |x - 5| \leq y \leq 4\sqrt{x} \}$ is $A$, then $3A$ is equal to
- JEE Main - 2025
- Area between Two Curves
Let $A = \begin{bmatrix} \cos \theta & 0 & -\sin \theta \\ 0 & 1 & 0 \\ \sin \theta & 0 & \cos \theta \end{bmatrix}$. If for some $\theta \in (0, \pi)$, $A^2 = A^T$, then the sum of the diagonal elements of the matrix $(A + I)^3 + (A - I)^3 - 6A$ is equal to
- JEE Main - 2025
- Matrices
Let $A = \{ z \in \mathbb{C} : |z - 2 - i| = 3 \}$, $B = \{ z \in \mathbb{C} : \text{Re}(z - iz) = 2 \}$, and $S = A \cap B$. Then $\sum_{z \in S} |z|^2$ is equal to
- JEE Main - 2025
- Determinants
Let $C$ be the circle $x^2 + (y - 1)^2 = 2$, $E_1$ and $E_2$ be two ellipses whose centres lie at the origin and major axes lie on the $x$-axis and $y$-axis respectively. Let the straight line $x + y = 3$ touch the curves $C$, $E_1$, and $E_2$ at $P(x_1, y_1)$, $Q(x_2, y_2)$, and $R(x_3, y_3)$ respectively. Given that $P$ is the mid-point of the line segment $QR$ and $PQ = \frac{2\sqrt{2}}{3}$, the value of $9(x_1 y_1 + x_2 y_2 + x_3 y_3)$ is equal to
- JEE Main - 2025
- Coordinate Geometry
Concepts Used:
Surface Area and Volume
Surface area and volume are two important concepts in geometry that are used to measure the size and shape of three-dimensional objects.
Surface area is the measure of the total area that the surface of an object covers. It is expressed in square units, such as square meters or square inches. To calculate the surface area of an object, we find the area of each face or surface and add them together. For example, the surface area of a cube is equal to six times the area of one of its faces.
Volume, on the other hand, is the measure of the amount of space that an object takes up. It is expressed in cubic units, such as cubic meters or cubic feet. To calculate the volume of an object, we measure the length, width, and height of the object and multiply these three dimensions together. For example, the volume of a cube is equal to the length of one of its edges cubed.
Surface area and volume are important in many fields, such as architecture, engineering, and manufacturing. For example, surface area is used to calculate the amount of material needed to cover an object, while volume is used to determine the amount of space that a container can hold. Understanding surface area and volume is also important in calculus and physics, where they are used to model the behavior of objects in three-dimensional space.