Rod AB of radius 2 r is joined with rod BC of radius r . They are of same material and are of same length. The combination carries a current I. Choose the correct statement.

The statement "a is not less than 4 " is correctly represented by
In the figure shown, the current carrying loop is fixed, where as current carrying straight conductor is free to move. Then straight wire will (ignore gravity)

Two friends A and B watched a car from the top of their buildings. Angle of depression for A was $10^{\circ}$ more than angle of depression for B , then

A convex mirror of focal length $f$ produces an image of size equal to $\frac{1}{n}$ times the size of the object. Then the object distance is
Total surface area of a sphere $S$ with radius $\sqrt{2}+\sqrt{3} \mathrm{ cm}$ is
The angle between the hour arm and the minute arm of a clock at 2:10 a.m. is
A craft teacher reshapes the wax from a cylinder of candle with section diameter 6 cm and the height 6 cm into a sphere. The radius of this sphere will be
A point object O is kept at origin. When a concave mirror $\mathrm{M}_{1}$ placed at $\mathrm{x}=6 \mathrm{ cm}$, image is formed at infinity. When $\mathrm{M}_{1}$ is replaced by another concave mirror $\mathrm{M}_{2}$ at same position, image is formed at $\mathrm{x}=$ 30 cm , then ratio of the focal length of $\mathrm{M}_{1}$ to that of $\mathrm{M}_{2}$ is
The number $3^{8}\left(3^{10}+6^{5}\right)+2^{3}\left(2^{12}+6^{7}\right)$ is
Melting point of a substance is $10^{\circ} \mathrm{C}$. What does this mean?
Let the number of rectangles formed by 6 horizontal and 4 vertical lines be n and those formed by 5 vertical and 5 horizontal lines be m then we have
The effective resistance between $A$ and $D$ in the circuit shown in the adjacent figure is

If ABCD is a rhombus and $\angle \mathrm{ABC}=60^{\circ}$ then
Three bulbs $\mathrm{B}_{1}, \mathrm{ B}_{2}$ and $\mathrm{B}_{3}$ having rated powers $100 \mathrm{ W}, 60 \mathrm{ W}$ and 60 W at 250 V are connected in a circuit as shown in the adjacent figure. If $\mathrm{W}_{1}, \mathrm{ W}_{2}$ and $\mathrm{W}_{3}$ are the output powers of the bulbs $\mathrm{B}_{1}, \mathrm{ B}_{2}$ and $\mathrm{B}_{3}$ respectively, then

If $\mathrm{a}, \mathrm{b}>0$ then
Following diagram shows refraction of parallel beam of light through a spherical surface. Identify the correct ray diagram

Tenth term in the sequence $12,18,20,28, \ldots$ is
In the diagram $\mathrm{M}_{1}$ and $\mathrm{M}_{2}$ are two plane mirrors at right angles to each other. O is a luminous point object. Consider two images formed due to first reflection at $\mathrm{M}_{1}$ and $\mathrm{M}_{2}$. The area of the triangle formed by the object and two images is

The probability of a point within an equilateral triangle with side 1-unit lying outside its in-circle (inscribed circle) is
A fisherman of height $h$ is standing on the bank of a lake. A fish in the water perceives his height as $h$ '. Then
A triangle has perimeter 316 and its sides are of integer length. The maximum possible area for such a triangle is achieved for
Object A is completely immersed in water. True weight of object A is $\mathrm{W}_{\mathrm{A}}$. Weight of water with beaker is $\mathrm{W}_{\mathrm{B}}$. Let B be the buoyant force. $\mathrm{W}_{1}$ and $\mathrm{W}_{2}$ are scale readings of spring balance and weighing scale respectively.

Number of numbers less than 40 having exactly four divisors is
Velocity of a particle moving along a straight line varies with time as shown in the figure. Net forces acting on the aprticle are $\mathrm{F}_{1}, \mathrm{ F}_{2}, \mathrm{ F}_{3}, \mathrm{ F}_{4}$ and $\mathrm{F}_{5}$ in the intervals $\mathrm{OA}, \mathrm{AB}, \mathrm{BC}, \mathrm{CD}$ and DE respectively. Indentify the correct statement

If set $X$ consists of three elements then the number of elements in the power set of power set of $X$ is
A wooden block $(\mathrm{W})$ is suspended by using a cord from a heavy steel ball (B). The entire system is dropped from a height. Neglecting air resistance, the tension in the cord is
In a n - sided regular polygon, the radius of the circum-circle is equal in length to the shortest diagonal. the number of values of $\mathrm{n}<60$ for which this can happen is
A circus performer of weight W is standing on a wire as shown in the figure. The tension in the wire is

Number of integers $n$ such that the number $1+n$ is a divisor of the number $1+n^{2}$ is :
In the following diagrams O is point object and I is its image formed by a concave mirror. Identify the diagram. In which position of image I is nearly correct.

If for $\mathrm{x}, \mathrm{y}>0$ we have $\frac{1}{\mathrm{x}}+\frac{1}{\mathrm{y}}=2$ then the minimum value of xy is
Two bodies $A$ and $B$ are charged with equal magnitude of charge but $A$ with positive charge and $B$ with negative. If $M_{A}$ and $M_{B}$ are masses before charging and $M^{I}{ }_{A}$ and $M^{I}{ }_{B}$ are the masses after charging the ( $\mathrm{m}_{0}$ is some constant mass)
The number of natural numbers $\mathrm{n} \leq 30$ for for which $\sqrt{\mathrm{n}+\sqrt{\mathrm{n}+\sqrt{\mathrm{n}+\ldots . .}}}$ is a natural number is
A conductor of length $L$ has a varying cross section with area $2 A$ at $P$ and $A$ at $Q$ as shown in the figure. If it carries a steady current I, then

The number of natural numbers $n \leq 30$ for which $\sqrt{n+\sqrt{n+\sqrt{n+\ldots \ldots . .}}}$ is a prime number is
Vessels A and B are made of conducting material. Both contain water. Vessel A floats in B. Vessel B is now heated at a uniform rate, then
The number of squares formed by 5 vertical and 4 horizontal lines (all are equispaced) is
Every major city in India has a pollution control board to monitor air and water pollution. The following data is from three different localities in Bangalore city from the year 2015.

ppb stands for parts per billion and ppm stands for parts per million. These are different units to express concentration. They are very similar to percentage (which is actually parts per hundred). Based on the above data, which place will you choose to live in?
A body thrown vertically up reaches a maximum height and returns back. Its acceleration is
The number of integers $a, b, c$ for which $a^{2}+b^{2}-8 c=3$ is

In 2026, the following Cheenta students have been successful for Indian Statistical Institute's M.Stat Entrance. They ranked within the first 50 in the entire country in these entrances. I.S.I. M.Stat Entrance

In 2026, the following Cheenta students have been successful for Indian Statistical Institute's B.Stat Entrance and Chennai Mathematical Institute's B.Sc. Math Entrance. They ranked within the first 200 in the entire country in these entrances. Most of these students attended the problem solving workshops regularly, which happen 5 days every week. CMI B.Sc. Math Entrance […]

In 2025, 8 students from Cheenta Academy cracked the prestigious Regional Math Olympiad. In this post, we will share some of their success stories and learning strategies. The Regional Mathematics Olympiad (RMO) and the Indian National Mathematics Olympiad (INMO) are two most important mathematics contests in India.These two contests are for the students who are […]

Cheenta Academy proudly celebrates the success of 27 current and former students who qualified for the Indian Olympiad Qualifier in Mathematics (IOQM) 2025, advancing to the next stage — RMO. This accomplishment highlights their perseverance and Cheenta’s ongoing mission to nurture mathematical excellence and research-oriented learning.