1
JEE Main 2023 (Online) 31st January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
A microscope is focused on an object at the bottom of a bucket. If liquid with refractive index $\frac{5}{3}$ is poured inside the bucket, then the microscope has to be raised by $30 \mathrm{~cm}$ to focus the object again. The height of the liquid in the bucket is :
A
$50 \mathrm{~cm}$
B
$18 \mathrm{~cm}$
C
$75 \mathrm{~cm}$
D
$12 \mathrm{~cm}$
2
JEE Main 2023 (Online) 30th January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A thin prism $P_1$ with an angle $6^{\circ}$ and made of glass of refractive index $1.54$ is combined with another prism $P_2$ made from glass of refractive index $1.72$ to produce dispersion without average deviation. The angle of prism $P_2$ is

A
$4.5^{\circ}$
B
$7.8^{\circ}$
C
$1.3^{\circ}$
D
$6^{\circ}$
3
JEE Main 2023 (Online) 30th January Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A person has been using spectacles of power $$-1.0$$ dioptre for distant vision and a separate reading glass of power $$2.0$$ dioptres. What is the least distance of distinct vision for this person :

A
50 cm
B
40 cm
C
30 cm
D
10 cm
4
JEE Main 2023 (Online) 29th January Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language

A scientist is observing a bacteria through a compound microscope. For better analysis and to improve its resolving power he should. (Select the best option)

A
Decrease the focal length of the eye piece.
B
Increase the wave length of the light
C
Increase the refractive index of the medium between the object and objective lens
D
Decrease the diameter of the objective lens
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