In the experiment to determine the speed of sound using a resonance column:

(A) Prongs of the tuning fork are kept in a vertical plane

(B) Prongs of the tuning fork are kept in a horizontal plane

(C) In one of the two resonances observed, the length of the resonating air column is close to the wavelength of sound in air

(D) In one of the two resonances observed, the length of the resonating air column is close to half of the wavelength of sound in air

In the experiment to determine the speed of sound using a…

Four combinations of two thin lenses are given in List I. The radius of curvature of all curved surfaces is r and the refractive index of all the lenses is 1.5. Match lens combinations in List I with their focal length in List II and select the correct answer using the code given below the lists.

	List I		List II
A.		$P .$	$2 r$
B.		$Q .$	$\frac{r}{2}$
C.		$R .$	$- r$
D.		$S .$	$r$

JEE Advanced 2014 Medium

Consider a hydrogen-like ionized atom with atomic number

Z

with a single electron. In the emission spectrum of this atom, the photon emitted in the

n = 2 t o n = 1

transition has energy

74.8 eV

higher than the photon emitted in the

n = 3 t o n = 2

transition. Given that the ionization energy of the hydrogen atom is

13.6 eV

, what is the value of

Z

?

JEE Advanced 2018 Medium

List-I shows four configurations, each consisting of a pair of ideal electric dipoles. Each dipole has a dipole moment of magnitude $p$, oriented as marked by arrows in the figures. In all the configurations the dipoles are fixed such that they are at a distance $2 r$ apart along the $x$ direction. The midpoint of the line joining the two dipoles is $X$. The possible resultant electric fields $\vec{E}$ at $X$ are given in List-II. Choose the option that describes the correct match between the entries in List-I to those in List-II.

		List-II
$(P)$	$(1)$	$\vec{E}=0$
$(Q)$	$(2)$	$\vec{E}=-\frac{p}{2 \pi \epsilon_0 \mathrm{r}^3} \hat{\mathrm{j}}$
$(R)$	$(3)$	$\vec{E}=-\frac{p}{4 \pi \epsilon_0 \mathrm{r}^3}(\hat{\mathrm{i}}-\hat{\mathrm{j}})$

$(S)$	$(4)$	$\vec{E}=\frac{p}{4 \pi \epsilon_0 \mathrm{r}^3}(2 \hat{\mathrm{i}}-\hat{\mathrm{j}})$
	$(5)$	$\vec{E}=\frac{p}{\pi \epsilon_0 \mathrm{r}^3} \hat{\mathrm{i}}$

JEE Advanced 2025 Hard

A beaker of radius

r

is filled with water

(refractive index \frac{4}{3})

up to a height

H

as shown in the figure on the left. The beaker is kept on a horizontal table rotating with angular speed

ω

. This makes the water surface curved so that the difference in the height of water level at the centre and at the circumference of the beaker is

h (h ≪ H, h ≪ r)

, as shown in the figure on the right. Take this surface to be approximately spherical with a radius of curvature

R .

Which of the following is/are correct? (

g

is the acceleration due to gravity)

JEE Advanced 2020 Hard

A train

S 1,

moving with a uniform velocity of

108 k m / h,

approaches another train

S 2

standing on a platform. An observer

O

moves with a uniform velocity of

36 k m / h

towards

S 2,

as shown in figure. Both the trains are blowing whistles of same frequency

120 H z .

When

O

is

600 m

away from

S 2

and distance between

S 1

and

S 2

is

800 m,

the number of beats heard by

O

is____
[Speed of the sound

= 330 m / s]

JEE Advanced 2019 Hard

A $20 \mathrm{~cm}$ long string, having a mass of $1.0 \mathrm{~g}$, is fixed at both the ends. The tension in the string is $0.5 \mathrm{~N}$. The string is set into vibration using an external vibrator of frequency 100 $\mathrm{Hz}$. Find the separation (in $\mathrm{cm}$ ) between the successive nodes on the string.

JEE Advanced 2009 Easy

		List-II
\((P)\)	\((1)\)	\(\vec{E}=0\)
\((Q)\)	\((2)\)	\(\vec{E}=-\frac{p}{2 \pi \epsilon_0 \mathrm{r}^3} \hat{\mathrm{j}}\)
\((R)\)	\((3)\)	\(\vec{E}=-\frac{p}{4 \pi \epsilon_0 \mathrm{r}^3}(\hat{\mathrm{i}}-\hat{\mathrm{j}})\)

\((S)\)	\((4)\)	\(\vec{E}=\frac{p}{4 \pi \epsilon_0 \mathrm{r}^3}(2 \hat{\mathrm{i}}-\hat{\mathrm{j}})\)
	\((5)\)	\(\vec{E}=\frac{p}{\pi \epsilon_0 \mathrm{r}^3} \hat{\mathrm{i}}\)

In the experiment to determine the speed of sound using a resonance column:

Answer & Solution

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