Explore topic-wise MCQs in Joint Entrance Exam - Main (JEE Main).

This section includes 8666 Mcqs, each offering curated multiple-choice questions to sharpen your Joint Entrance Exam - Main (JEE Main) knowledge and support exam preparation. Choose a topic below to get started.

4451.

The angle of elevation of a tower at a point distant d meters from its base is 30°. If the tower is  20 meters high, then the value of d is [MP PET 1982, 88]

A. \[10\sqrt{3}m\]
B. \[\frac{20}{\sqrt{3}}m\]
C. \[20\sqrt{3}m\]
D. \[10\]m
Answer» D. \[10\]m
4452.

Two vertical poles of equal heights are 120 m apart. On the line joining their bottoms, A and B are two points. Angle of elevation of the top of one pole from A is 45o and that of the other pole from B is also 45o. If AB =  30 m, then the height of each pole is

A. 40 m
B. 45 m
C. 50 m
D. 42 m
Answer» C. 50 m
4453.

If the angle of depression of a point A on the ground from the top of a tower be\[{{30}^{o}}\], then the angle of elevation of the top of the tower from the point A will be

A. \[{{60}^{o}}\]
B. \[{{45}^{o}}\]
C. \[{{30}^{o}}\]
D. None of these
Answer» D. None of these
4454.

From a point a metre above a lake the angle of elevation of a cloud is a and the angle of depression of its reflection is b. The height of the cloud is [Roorkee 1983; EAMCET 1983, 85]

A. \[\frac{a\sin \,(\alpha +\beta )}{\sin \,(\alpha -\beta )}\] metre
B. \[\frac{a\sin \,(\alpha +\beta )}{\sin \,(\beta -\alpha )}\] metre
C. \[\frac{a\sin \,(\beta -\alpha )}{\sin \,(\alpha +\beta )}\] metre
D. None of these
Answer» C. \[\frac{a\sin \,(\beta -\alpha )}{\sin \,(\alpha +\beta )}\] metre
4455.

An aeroplane flying horizontally 1 km above the ground is observed at an elevation of 60o and after 10 seconds the elevation is observed to be\[{{30}^{o}}\]. The uniform speed of the aeroplane in \[km/h\] is [IIT 1965]

A. 240
B. \[240\sqrt{3}\]
C. \[60\sqrt{3}\]
D. None of these
Answer» C. \[60\sqrt{3}\]
4456.

The angle of elevation of a tower from a point A due south of it is 30o and from a point B due west of it is 45o. If the height of the tower be 100 metres, then AB =

A. 150 m
B. 200 m
C. 173.2 m
D. 141.4 m
Answer» C. 173.2 m
4457.

A tower subtends an angle a  at a point A in the plane of its base and the angle of depression of the foot of the tower at a point l meters just above A is b. The height of the tower is    [MP PET 1990; RPET 1990]

A. \[l\,\,\tan \,\beta \,\cot \,\alpha \]
B. \[l\,\,\tan \,\alpha \,\cot \,\beta \]
C. \[l\,\,\tan \,\,\alpha \,\,\tan \,\beta \]
D. \[l\,\,\cot \,\,\alpha \,\,\cot \,\beta \]
Answer» C. \[l\,\,\tan \,\,\alpha \,\,\tan \,\beta \]
4458.

An observer in a boat finds that the angle of elevation of a tower standing on the top of a cliff is 60o and that of the top of cliff is 30o. If the height of the tower be 60 meters, then the height of the cliff is [Roorkee 1982]

A. 30 m
B. \[60\sqrt{3}\,\,m\]
C. \[20\sqrt{3}\,\,m\]
D. None of these
Answer» B. \[60\sqrt{3}\,\,m\]
4459.

From the top of a light house 60 meters high with its base at the sea level, the angle of depression of a boat is 15o. The distance of the boat from the foot of light house is   [MNR 1988; IIT 1983; MP PET 1994, 2001; UPSEAT 2000]

A. \[\left( \frac{\sqrt{3}-1}{\sqrt{3}+1} \right)\,60\,\,m\]
B. \[\left( \frac{\sqrt{3}+1}{\sqrt{3}-1} \right)\,60\,\,m\]
C. \[\left( \frac{\sqrt{3}+1}{\sqrt{3}-1} \right)\,\,\,m\]
D. None of these
Answer» C. \[\left( \frac{\sqrt{3}+1}{\sqrt{3}-1} \right)\,\,\,m\]
4460.

The angle of elevation of the top of a tower from a point    20 metre away from its base is 45o. The height of the tower is [MP PET 1984, 89]

A. 10 m
B. 20 m
C. 40 m
D. \[20\sqrt{3}\] m
Answer» C. 40 m
4461.

The length of the shadow of a pole inclined at 10o to the vertical towards the sun is 2.05 metres, when the elevation of the sun is 38o. The length of the pole is [Roorkee 1976]

A. \[\frac{2.05\,\,\sin \,\,{{38}^{o}}}{\sin \,{{42}^{o}}}\]
B. \[\frac{2.05\,\,\sin \,\,{{42}^{o}}}{\sin \,{{38}^{o}}}\]
C. \[\frac{2.05\,\,\cos \,\,{{38}^{o}}}{\cos \,\,{{42}^{o}}}\]
D. None of these
Answer» B. \[\frac{2.05\,\,\sin \,\,{{42}^{o}}}{\sin \,{{38}^{o}}}\]
4462.

The angle of elevation of the top of a tower at point on the ground is\[{{30}^{o}}\]. If on walking 20 metres toward the tower, the angle of elevation become\[{{60}^{o}}\], then the height of the tower is [MNR 1975; IIT 1967]

A. 10 metre
B. \[\frac{10}{\sqrt{3}}metre\]
C. \[10\sqrt{3}metre\]
D. None of these
Answer» D. None of these
4463.

If \[a,\ b,\ c\] are three distinct positive real numbers which are in H.P., then \[\frac{3a+2b}{2a-b}+\frac{3c+2b}{2c-b}\] is

A. Greater than or equal to 10
B. Less than or equal to 10
C. Only equal to 10
D. None of these
Answer» E.
4464.

The first term of a harmonic progression is 1/7 and the second term is 1/9. The \[{{12}^{th}}\] term is [MP PET 1994]

A. 43466
B. 47119
C. 42736
D. 46388
Answer» C. 42736
4465.

If \[{{a}_{1}},\ {{a}_{2}},\ {{a}_{3}},...............,\ {{a}_{n}}\] are in H.P., then \[{{a}_{1}}{{a}_{2}}+{{a}_{2}}{{a}_{3}}+\] \[..........+{{a}_{n-1}}{{a}_{n}}\] will be equal to [IIT 1975]

A. \[{{a}_{1}}{{a}_{n}}\]
B. \[n{{a}_{1}}{{a}_{n}}\]
C. \[(n-1){{a}_{1}}{{a}_{n}}\]
D. None of these
Answer» D. None of these
4466.

If \[{{5}^{th}}\] term of a H.P. is \[\frac{1}{45}\]and \[{{11}^{th}}\] term is \[\frac{1}{69}\], then its \[{{16}^{th}}\]  term will be [RPET 1987,  97]

A. 32509
B. 31048
C. 29221
D. 28856
Answer» B. 31048
4467.

If \[x,\ y,\ z\] are in H.P., then the value of expression \[\log (x+z)+\log (x-2y+z)\] will be  [RPET 1985, 2000]

A. \[\log (x-z)\]
B. \[2\log (x-z)\]
C. \[3\log (x-z)\]
D. \[4\log (x-z)\]
Answer» C. \[3\log (x-z)\]
4468.

If \[a,\ b,\ c,\ d\] are in H.P., then [RPET 1991]

A. \[a+d>b+c\]
B. \[ad>bc\]
C. Both (a) and (b)
D. None of these
Answer» D. None of these
4469.

The fifth term of the H.P., \[2,\ 2\frac{1}{2},\ 3\frac{1}{3},.............\] will be  [MP PET 1984]

A. \[5\frac{1}{5}\]
B. \[3\frac{1}{5}\]
C. 44470
D. 10
Answer» E.
4470.

If the harmonic mean between \[a\] and \[b\] be \[H\], then \[\frac{H+a}{H-a}+\frac{H+b}{H-b}=\] [AMU 1998]

A. 4
B. 2
C. 1
D. \[a+b\]
Answer» C. 1
4471.

If \[a,\ b,\ c\] be in H.P., then

A. \[{{a}^{2}}+{{c}^{2}}>{{b}^{2}}\]
B. \[{{a}^{2}}+{{b}^{2}}>2{{c}^{2}}\]
C. \[{{a}^{2}}+{{c}^{2}}>2{{b}^{2}}\]
D. \[{{a}^{2}}+{{b}^{2}}>{{c}^{2}}\]
Answer» D. \[{{a}^{2}}+{{b}^{2}}>{{c}^{2}}\]
4472.

If \[\frac{{{a}^{n+1}}+{{b}^{n+1}}}{{{a}^{n}}+{{b}^{n}}}\] be the harmonic mean between \[a\] and \[b\], then the value of \[n\] is [Assam  PET 1986]

A. 1
B. \[-1\]
C. 0
D. 2
Answer» C. 0
4473.

The sixth H.M. between 3 and \[\frac{6}{13}\] is [RPET 1996]

A.   \[\frac{63}{120}\]
B.   \[\frac{63}{12}\]
C.   \[\frac{126}{105}\]
D.   \[\frac{120}{63}\]
Answer» B.   \[\frac{63}{12}\]
4474.

Which number should be added to the numbers 13, 15, 19 so that the resulting numbers be the consecutive terms of a H.P.

A. 7
B. 6
C. \[-6\]
D. \[-7\]
Answer» E.
4475.

The harmonic mean of \[\frac{a}{1-ab}\] and \[\frac{a}{1+ab}\] is [MP PET 1996; Pb. CET 2001]

A.   \[\frac{a}{\sqrt{1-{{a}^{2}}{{b}^{2}}}}\]
B.   \[\frac{a}{1-{{a}^{2}}{{b}^{2}}}\]
C. \[a\]
D. \[\frac{1}{1-{{a}^{2}}{{b}^{2}}}\]
Answer» D. \[\frac{1}{1-{{a}^{2}}{{b}^{2}}}\]
4476.

H.M. between the roots of the equation \[{{x}^{2}}-10x+11=0\] is [MP PET 1995]

A. \[\frac{1}{5}\]
B. \[\frac{5}{21}\]
C. \[\frac{21}{20}\]
D. \[\frac{11}{5}\]
Answer» E.
4477.

If the harmonic mean between \[a\] and \[b\] be \[H\], then the value of  \[\frac{1}{H-a}+\frac{1}{H-b}\] is

A. \[a+b\]
B. \[ab\]
C. \[\frac{1}{a}+\frac{1}{b}\]
D. \[\frac{1}{a}-\frac{1}{b}\]
Answer» D. \[\frac{1}{a}-\frac{1}{b}\]
4478.

If \[H\] is the harmonic mean between \[p\] and \[q\], then the value of  \[\frac{H}{p}+\frac{H}{q}\]  is [MNR 1990; UPSEAT 2000,  01]

A. 2
B. \[\frac{pq}{p+q}\]
C. \[\frac{p+q}{pq}\]
D. None of these
Answer» B. \[\frac{pq}{p+q}\]
4479.

The 4th term of a H.P. is \[\frac{3}{5}\] and 8th term is \[\frac{1}{3},\] then its 6th term is [MP PET 2003]

A. \[\frac{1}{6}\]
B. \[\frac{3}{7}\]
C. \[\frac{1}{7}\]
D. \[\frac{3}{5}\]
Answer» C. \[\frac{1}{7}\]
4480.

In a H.P., pth term is q and the qth term is p. Then pqth term is   [Karnataka CET 2002]

A. 0
B. 1
C. pq
D. \[pq(p+q)\]
Answer» C. pq
4481.

If sixth term of a H.P. is \[\frac{1}{61}\] and its tenth term is \[\frac{1}{105},\] then first term of that H.P. is [Karnataka CET 2001]

A. \[\frac{1}{28}\]
B. \[\frac{1}{39}\]
C. \[\frac{1}{6}\]
D. \[\frac{1}{17}\]
Answer» D. \[\frac{1}{17}\]
4482.

If the \[{{7}^{th}}\] term of a H.P. is \[\frac{1}{10}\] and the \[{{12}^{th}}\] term is \[\frac{1}{25}\], then the \[{{20}^{th}}\] term is [MP PET 1997]

A. \[\frac{1}{37}\]
B.   \[\frac{1}{41}\]
C.   \[\frac{1}{45}\]
D.   \[\frac{1}{49}\]
Answer» E.
4483.

If the \[{{7}^{th}}\] term of a harmonic progression is 8 and the \[{{8}^{th}}\]term is 7, then its \[{{15}^{th}}\] term is [MP PET 1996]

A. 16
B. 14
C. \[\frac{27}{14}\]
D.   \[\frac{56}{15}\]
Answer» E.
4484.

If the vertices of a quadrilateral be \[A=1+2i,\] \[B=-3+i,\] \[C=-2-3i\] and \[D=2-2i\],  then the quadrilateral is

A. Parallelogram
B. Rectangle
C. Square
D. Rhombus
Answer» D. Rhombus
4485.

If \[|z|=2\], then the points representing the complex numbers \[-1+5z\] will lie on a

A. Circle
B. Straight line
C. Parabola
D. None of these
Answer» B. Straight line
4486.

If \[z=\sqrt{2}-i\sqrt{2}\] is rotated through an angle \[45{}^\circ \] in the anti-clockwise direction about the origin, then the coordinates of its new position are [Kerala (Engg.) 2005]

A. (2, 0)
B. (\[\sqrt{2},\,\sqrt{2}\])
C. \[(\sqrt{2},\,-\sqrt{2}\])
D. \[(\sqrt{2},0)\]
E. (4, 0)
Answer» E. (4, 0)
4487.

If \[|z-2-3i|+|z+2-6i|=4\], where \[i=\sqrt{-1}\], then locus of \[P(z)\] is [DCE 2005]

A. An ellipse
B. \[\varphi \]
C. Line segment joining of point \[2+3i\] and \[-2+6i\]
D. None of these
Answer» C. Line segment joining of point \[2+3i\] and \[-2+6i\]
4488.

The number of solutions for the equations \[|z-1|=|z-2|=\] \[|z-i|\] is  [Orissa JEE 2005]

A. One solution
B. 3 solutions
C. 2 solutions
D. No solution
Answer» B. 3 solutions
4489.

PQ and PR are two infinite rays. QAR is an arc. Point lying in the shaded region excluding the boundary satisfies  [IIT Screening 2005]

A. \[|z-1|>2;|\arg (z-1)|\,<\frac{\pi }{4}\]
B. \[|z-1|>2;|\arg (z-1)|\,<\frac{\pi }{2}\]
C. \[|z+1|>2;|\arg (z+1)|\,<\frac{\pi }{4}\]
D. \[|z+1|>2;|\arg (z+1)|\,<\frac{\pi }{2}\]
Answer» D. \[|z+1|>2;|\arg (z+1)|\,<\frac{\pi }{2}\]
4490.

If \[|8+z|+|z-8|=16\] where z is a complex number, then the point z will lie on [J & K 2005]

A. A circle
B. An ellipse
C. A straight line
D. None of these
Answer» C. A straight line
4491.

If \[a\] and \[b\] are real numbers between 0 and 1 such that the points \[{{z}_{1}}=a+i,{{z}_{2}}=1+bi\] and  \[{{z}_{3}}=0\] form an equilateral triangle, then [IIT 1989]

A. \[a=b=2+\sqrt{3}\]
B. \[a=b=2-\sqrt{3}\]
C. \[a=2-\sqrt{3},b=2+\sqrt{3}\]
D. None of these
Answer» C. \[a=2-\sqrt{3},b=2+\sqrt{3}\]
4492.

If \[w=\frac{z}{z-\frac{1}{3}i}\] and \[|w|=1\], then z lies on [AIEEE 2005]

A. A straight line
B. A parabola
C. An ellipse
D. A circle
Answer» B. A parabola
4493.

The equation \[|z-5i|\div |z+5i|\,=12,\] where \[z=x+iy,\] represents a/an [AMU 1999]

A. Circle
B. Ellipse
C. Parabola
D. No real curve
Answer» B. Ellipse
4494.

If \[z=x+iy\] and \[arg\,\left( \frac{z-2}{z+2} \right)=\frac{\pi }{6}\], then locus of z  is [RPET 2002]

A. A straight line
B. A circle
C. A parabola
D. An ellipse
Answer» C. A parabola
4495.

If \[|{{z}^{2}}-1|\,=\,|z{{|}^{2}}+1\], then \[z\]lies on [AIEEE 2004]

A. An ellipse
B. The imaginary axis
C. A circle
D. The real axis
Answer» C. A circle
4496.

The locus of the point z satisfying \[arg\left( \frac{z-1}{z+1} \right)=k,\] (where k is non zero) is [Orissa JEE 2002]

A. Circle with centre on y-axis
B. Circle with centre on x-axis
C. A straight line parallel to x-axis
D. A straight line making an angle \[{{60}^{o}}\] with the x-axis
Answer» B. Circle with centre on x-axis
4497.

Locus of the point z satisfying the equation \[|iz-1|\]+ \[|z-i|=2\] is [Roorkee 1999]

A. A straight line
B. A circle
C. An ellipse
D. A pair of straight lines
Answer» B. A circle
4498.

If \[z=x+iy\] is a complex number satisfying \[{{\left| z+\frac{i}{2} \right|}^{2}}=\] \[\,\,{{\left| z-\frac{i}{2} \right|}^{2}},\] then the locus of z is [EAMCET 2002]

A. \[2y=x\]
B. \[y=x\]
C. y-axis
D. x-axis
Answer» E.
4499.

If \[z=x+iy\] and \[|z-2+i|\,=\,|z-3-i|,\] then locus of z is [RPET 1999]

A. \[2x+4y-5=0\]
B. \[2x-4y-5=0\]
C. \[x+2y=0\]
D. \[x-2y+5=0\]
Answer» B. \[2x-4y-5=0\]
4500.

If three complex numbers are in A.P., then they lie on     [IIT 1985; DCE 2001; Pb. CET 2003]

A. A circle in the complex plane
B. A straight line in the complex plane
C. A parabola in the complex plane
D. None of these
Answer» C. A parabola in the complex plane