JEE Mains · Physics · STD 12 - 8. Electromagnetic waves
A beam of light travelling along \(X\)-axis is described by the electric field \(E _{ y }=900 \sin \omega( t - x / c )\). The ratio of electric force to magnetic force on a charge \(q\) moving along \(Y\)-axis with a speed of \(3 \times 10^{7}\,ms ^{-1}\) will be. [Given speed of light \(=3 \times 10^{8}\,ms ^{-1}\) ]
- A \(1: 1\)
- B \(1: 10\)
- C \(10: 1\)
- D \(1: 2\)
Answer & Solution
Correct Answer
(C) \(10: 1\)
Step-by-step Solution
Detailed explanation
\(E _{ y }=900 \sin \left(\omega t -\frac{\omega x }{ c }\right)\) \(E _{0}=900\) \(F _{ E }= q E _{0}\) \(F _{ B }= qvB _{0}\) \(\frac{ F _{ E }}{ F _{ B }}=\frac{ E _{0}}{ vB }=\frac{ c }{ v }=\frac{3 \times 10^{8}}{3 \times 10^{7}}=10: 1\)
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
- An experiment is performed to obtain the value of acceleration due to gravity \(g\) by using a simple pendulum of length \(L\). In this experiment time for \(100\, oscillations\) is measured by using a watch of \(1\, second\) least count and the value is \(90.0\, seconds\). The length \(L\) is measured by using a meter scale of least count \(1\, mm\) and the value is \(20.0\, cm\). The error in the determination of \(g\) would be ........... \(\%\)JEE Mains 2014 Hard
- Two radioactive substances A and B of mass numbers \(200\) and \(212\) respectively, shows spontaneous \(\alpha\)-decay with same \(Q\) value of \(1\) MeV. The ratio of energies of \(\alpha\)-rays produced by A and B is ________.JEE Mains 2026 Medium
- A signal of \(0.1\, kW\) is transmitted in a cable. The attenuation of cable is \(-5 \,dB\) per \(km\) and cable length is \(20\, km\). The power received at receiver is \(10^{-x} \, W\). The value of \(x\) is ....... . \(\left[\right.\) Gain in \(\left. dB =10 \log _{10}\left(\frac{ P _{0}}{ P _{i}}\right)\right]\)JEE Mains 2021 Hard
- Three solid spheres each of mass \(\mathrm{m}\) and diameter \(d\) are stuck together such that the lines connecting the centres form an equilateral triangle of side of length \(d\). The ratio \(\mathrm{I}_{0} / \mathrm{I}_{\mathrm{A}}\) of moment of inertia \(\mathrm{I}_{0}\) of the system about an axis passing the centroid and about center of any of the spheres \(\mathrm{I}_{\mathrm{A}}\) and perpendicular to the plane of the triangle is
JEE Mains 2020 Hard - Match the LIST-I with LIST-II
LIST-I LIST-II (A) Boltzmann constant I. \(\mathrm{ML}^2 \mathrm{~T}^{-1}\) (B) Coefficient of viscosity II. \(\mathrm{MLT}^{-3} \mathrm{~K}^{-1}\) (C) Planck's constant III. \(\mathrm{ML}^2 \mathrm{~T}^{-2} \mathrm{~K}^{-1}\) (D) Thermal conductivity IV. \(\mathrm{ML}^{-1} \mathrm{~T}^{-1}\)
Choose the correct answer from the options given below :JEE Mains 2025 Medium - A pipe open at both ends has a fundamental frequency \(f\) in air. The pipe is dipped vertically in water so that half of it is in water. The fundamental frequency of the air column is now ..... \(f\)JEE Mains 2016 Medium
More PYQs from JEE Mains
- Let \(A\) be a point on the line \(\vec r = \left( {1 - 3\mu } \right)\hat i + \left( {\mu - 1} \right)\hat j + \left( {2 + 5\mu } \right)\hat k\) and \(B(3, 2, 6)\) be a point in the space. Then the value of \(\mu \) for which the vector \(\overrightarrow {AB} \) is parallel to the plane \(x -4y +3z = 1\) isJEE Mains 2019 Hard
- In an electron microscope, the resolution that can be achieved is of the order of the wavelength of electrons used. To resolve a width of \(7.5 \times 10^{-12}\, m\), the minimum electron energy required is close to .............. \(keV\)JEE Mains 2019 Medium
- If \(\sum_{\mathrm{r}=0}^{10}\left(\frac{10^{\mathrm{r}+1}-1}{10^{\mathrm{r}}}\right) \cdot{ }^{11} \mathrm{C}_{\mathrm{r}+1}=\frac{\alpha^{11}-11^{11}}{10^{10}}\), then \(\alpha\) is equal to :JEE Mains 2025 Hard
- A heat engine operates between a cold reservoir at temperature \({T}_{2}=400\, {K}\) and a hot reservoir at temperature \({T}_{1} .\) It takes \(300 \,{J}\) of heat from the hot reservoir and delivers \(240\, {J}\) of heat to the cold reservoir in a cycle. The minimum temperature of the hot reservoir has to be \(....{K}\)JEE Mains 2021 Medium
- A ray of light coming from the point \(P(1,2)\) gets reflected from the point \(\mathrm{Q}\) on the \(\mathrm{x}\)-axis and then passes through the point \(R(4,3)\). If the point \(S(h\), \(\mathrm{k})\) is such that \(\mathrm{PQRS}\) is a parallelogram, then \(\mathrm{hk}^2\) is equal toJEE Mains 2024 Hard
- \(\lim\limits _{x \rightarrow 0} \frac{\cos (\sin x)-\cos x}{x^{4}}\) is equal to :JEE Mains 2022 Hard