1
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0
The focal lengths of the objective and eyepiece of a compound microscope are 1 cm and 10 cm respectively. Length of the tube is 25 cm . If the final image is formed at infinity , the magnifying power of the microscope is :
A
70
B
35
C
7.0
D
3.5
2
COMEDK 2025 Afternoon Shift
MCQ (Single Correct Answer)
+1
-0
What is the velocity of light in vacuum if the velocity of light in a medium of refractive index 1.2 is ' v ' $\mathrm{ms}^{-1}$ ?
A
$\left(\frac{v}{1.2}\right) m s^{-1}$
B
$(2.4 v) \mathrm{ms}^{-1}$
C
$(1.2 v) \mathrm{ms}^{-1}$
D
$3 \times 10^8 \mathrm{~ms}^{-1}$
3
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
One surface of a lens is convex and the other is concave. If the radii of curvatures are $R$ and $r$ respectively, the lens will be convex if
A
$R >r$
B
$R< r$
C
$R=\frac{1}{r}$
D
$R=r$
4
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
A convex lens forms a real image of an object with magnification $m_1$. The lens is moved towards the object to obtain another real image of magnification $m_2$. The image distance is increased by $x$. The focal length of the lens is
A
$\left(\frac{m_2}{m_1}\right) x$
B
$\left(\frac{m_1}{m_2}\right) x$
C
$\frac{x}{m_2-m_1}$
D
$x\left(m_2-m_1\right)$
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