1
JEE Main 2023 (Online) 31st January Morning Shift
Numerical
+4
-1

In a medium the speed of light wave decreases to $$0.2$$ times to its speed in free space The ratio of relative permittivity to the refractive index of the medium is $$x: 1$$. The value of $$x$$ is _________.

(Given speed of light in free space $$=3 \times 10^{8} \mathrm{~m} \mathrm{~s}^{-1}$$ and for the given medium $$\mu_{\mathrm{r}}=1$$)

2
JEE Main 2023 (Online) 30th January Evening Shift
Numerical
+4
-1

In a Young's double slit experiment, the intensities at two points, for the path differences $\frac{\lambda}{4}$ and $\frac{\lambda}{3}$ ( $\lambda$ being the wavelength of light used) are $I_{1}$ and $I_{2}$ respectively. If $I_{0}$ denotes the intensity produced by each one of the individual slits, then $\frac{I_{1}+I_{2}}{I_{0}}=$ __________.

3
JEE Main 2023 (Online) 30th January Morning Shift
Numerical
+4
-1

In an experiment for estimating the value of focal length of converging mirror, image of an object placed at $$40 \mathrm{~cm}$$ from the pole of the mirror is formed at distance $$120 \mathrm{~cm}$$ from the pole of the mirror. These distances are measured with a modified scale in which there are 20 small divisions in $$1 \mathrm{~cm}$$. The value of error in measurement of focal length of the mirror is $$\frac{1}{\mathrm{~K}} \mathrm{~cm}$$. The value of $$\mathrm{K}$$ is __________.

4
JEE Main 2023 (Online) 30th January Morning Shift
Numerical
+4
-1

In Young's double slit experiment, two slits $$S_{1}$$ and $$S_{2}$$ are '$$d$$' distance apart and the separation from slits to screen is $$\mathrm{D}$$ (as shown in figure). Now if two transparent slabs of equal thickness $$0.1 \mathrm{~mm}$$ but refractive index $$1.51$$ and $$1.55$$ are introduced in the path of beam $$(\lambda=4000$$ $$\mathop A\limits^o$$) from $$\mathrm{S}_{1}$$ and $$\mathrm{S}_{2}$$ respectively. The central bright fringe spot will shift by ___________ number of fringes.

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