JEE Mains · Physics · STD 12 - 8. Electromagnetic waves
A laser beam has intensity of \( 4.0\times10^{14} W/m^{2} \). The amplitude of magnetic field associated with beam is__________ T. (Take \( \epsilon_{0}=8.85\times10^{-12} C^{2}/Nm^{2} \) and \( c=3\times10^{8} m/s \))
- A 2.0
- B 18.3
- C 5.5
- D 1.83
Answer & Solution
Correct Answer
(D) 1.83
Step-by-step Solution
Detailed explanation
\(I =\frac{1}{2} \epsilon_0 E _0^2 \cdot C\) \(\therefore E _0=\sqrt{\frac{2 I }{\epsilon_0 C }}\) \(\& \frac{ E _0}{B_0}= C\) \(\therefore B_0=\frac{E_0}{C}=\frac{1}{C} \sqrt{\frac{2 I}{\epsilon_0 C}}\)…
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Physics
- Two stars of masses \(3\times10^{31}\, kg\) each, and at distance \(2\times10^{11}\, m\) rotate in a plane about their common centre of mass \(O. A\) meteorite passes through \(O\) moving perpendicular to the star’s rotation plane. In order to escape from the gravitational field of this double star, the minimum speed that meteorite should have at \(O\) is : (Take Gravitational constant \(G = 6.67\times10^{-11}\, Nm^2\, kg^{-2}\))JEE Mains 2019 Medium
- An infinite number of point charges, each carrying \(1 \,\mu C\) charge, are placed along the y-axis at \(y=1\, m , 2\, m , 4 \,m , 8\, m \ldots \ldots \ldots \ldots \ldots\) The total force on a \(1 \,C\) point charge, placed at the origin, is \(x \times 10^{3}\, N\). The value of \(x\), to the nearest integer, is ......... [Take \(\left.\frac{1}{4 \pi \epsilon_{0}}=9 \times 10^{9} \,Nm ^{2} / C ^{2}\right]\)JEE Mains 2021 Medium
- On celcius scale the temperature of body increases by \(40^{\circ} \mathrm{C}\). The increase in temperature on Fahrenheit scale is _______.JEE Mains 2024 Hard
- If \(\mu_0\) and \(\varepsilon_0\) are the permeability and permittivity of free space, respectively, then the dimension of \(\left(\frac{1}{\mu_0 \varepsilon_0}\right)\) is :JEE Mains 2025 Easy
- A parallel plate capacitor is of area \(6\, cm^2\) and a separation \(3\, mm\). The gap is filled with three dielectric materials of equal thickness (see figure) with dielectric constants \(K_1 = 10, K_2 = 12\) and \(K_3 = 14\). The dielectric constant of a material which when fully inserted in above capacitor, gives same capacitance would be
JEE Mains 2019 Hard - Given below are two statements: Statement \(I :\) Maximum power is dissipated in a circuit containing an inductor, a capacitor and a resistor connected in series with an \(AC\) source, when resonance occurs Statement \(II :\) Maximum power is dissipated in a circuit containing pure resistor due to zero phase difference between current and voltage. In the light of the above statements, choose the correct answer from the options given below :JEE Mains 2023 Medium
More PYQs from JEE Mains
- Let the positive numbers \(a _1, a _2, a _3, a _4\) and \(a _5\) be in a G.P. Let their mean and variance be \(\frac{31}{10}\) and \(\frac{ m }{ n }\) respectively, where \(m\) and \(n\) are co-prime. If the mean of their reciprocals is \(\frac{31}{40}\) and \(a_3+a_4+a_5=14\), then \(m + n\) is equal to \(.........\).JEE Mains 2023 Hard
- \(5 -\) digit numbers are to be formed using \(2, 3, 5, 7, 9\) without repeating the digits. If \(p\) be the number of such numbers that exceed \(20000\) and \(q\) be the number of those that lie between \(30000\) and \(90000\), then \(p : q\) isJEE Mains 2013 Hard
- If \(\int_{\frac{\pi}{6}}^{\frac{\pi}{3}} \sqrt{1-\sin 2 x} d x=\alpha+\beta \sqrt{2}+\gamma \sqrt{3}\), where \(\alpha, \beta\) and \(\gamma\) are rational numbers, then \(3 \alpha+4 \beta-\gamma\) is equal to ...........JEE Mains 2024 Hard
- The value of the integral \(\int \limits_{1 / 2}^2 \frac{\tan ^{-1} x}{x} d x\) is equal toJEE Mains 2023 Hard
- Two parallel long current carrying wire separated by a distance \(2 \mathrm{r}\) are shown in the figure. The ratio of magnetic field at \(\mathrm{A}\) to the magnetic field produced at \(C\) is \(\frac{x}{7}\). The value of \(x\) is _______.
JEE Mains 2024 Hard - As shown in the figure, a bob of mass \(\mathrm{m}\) is tied by a massless string whose other end portion is wound on a fly wheel (disc) of radius \(\mathrm{r}\) and mass \(m\). When released from rest the bob starts falling vertically. When it has covered a distance of \(h\). the angular speed of the wheel will be
JEE Mains 2020 Medium