1
JEE Main 2021 (Online) 26th February Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
The incident ray, reflected ray and the outward drawn normal are denoted by the unit vectors $$\overrightarrow a $$, $$\overrightarrow b $$ and $$\overrightarrow c $$ respectively. Then choose the correct relation for these vectors.
A
$$\overrightarrow b $$ = $$\overrightarrow a $$ + 2$$\overrightarrow c $$
B
$$\overrightarrow b $$ = $$\overrightarrow a $$ $$-$$ 2 ($$\overrightarrow a $$ . $$\overrightarrow c $$)$$\overrightarrow c $$
C
$$\overrightarrow b $$ = 2$$\overrightarrow a $$ + $$\overrightarrow c $$
D
$$\overrightarrow b $$ = $$\overrightarrow a $$ $$-$$ $$\overrightarrow c $$
2
JEE Main 2021 (Online) 26th February Evening Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Given below are two statements : one is labeled as Assertion A and the other is labeled as Reason R.

Assertion A : For a simple microscope, the angular size of the object equals the angular size of the image.

Reason R : Magnification is achieved as the small object can be kept much closer to the eye than 25 cm and hence it subtends a large angle.

In the light of the above statements, choose the most appropriate answer from the options given below :
A
A is true but R is false
B
A is false but R is true
C
Both A and R are true and R is the correct explanation of A
D
Both A and R are true but R is NOT the correct explanation of A
3
JEE Main 2021 (Online) 26th February Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
A short straight object of height 100 cm lies before the central axis of a spherical mirror whose focal length has absolute value | f | = 40 cm. The image of object produced by the mirror is of height 25 cm and has the same orientation of the object. One may conclude from the information :
A
Image is real, same side of convex mirror.
B
Image is virtual, opposite side of convex mirror.
C
Image is virtual, opposite side of concave mirror.
D
Image is real, same side of concave mirror.
4
JEE Main 2021 (Online) 24th February Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
The focal length f is related to the radius of curvature r of the spherical convex mirror by :
A
f = r
B
f = $$-$$ r
C
f = +$${{1 \over 2}}$$ r
D
f = $$-$$$${{1 \over 2}}$$ r
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