31. A triangle is formed with vertices (0, 0), (0, 100) and (100, 100). Wh

A triangle is formed with vertices (0, 0), (0, 100) and (100, 100). What is the number of points inside the triangle with integer coordinates?

5000
4999
4851
4800
This question was previously asked in
UPSC CAPF – 2016
The correct option is C) 4851.
The problem asks for the number of points with integer coordinates strictly *inside* the triangle formed by vertices (0, 0), (0, 100), and (100, 100).
The vertices of the triangle are A=(0, 0), B=(0, 100), and C=(100, 100).
The lines forming the boundaries of the triangle are:
1. The line segment AB is along the y-axis, from y=0 to y=100 (x=0).
2. The line segment BC is along the line y=100, from x=0 to x=100.
3. The line segment AC connects (0, 0) and (100, 100). The equation of this line is y = x.

A point (x, y) is strictly inside this triangle if it satisfies the following conditions:
1. It must be to the right of the line x=0: x > 0.
2. It must be below the line y=100: y < 100. 3. It must be above the line y=x: y > x.

Combining these, we are looking for integer coordinates (x, y) such that 0 < x < y < 100. Let's iterate through possible integer values for x. Since x > 0 and x < y < 100, the smallest possible integer value for x is 1. If x = 1, y must be an integer such that 1 < y < 100. Possible y values are 2, 3, ..., 99. The number of such y values is 99 - 2 + 1 = 98. If x = 2, y must be an integer such that 2 < y < 100. Possible y values are 3, 4, ..., 99. The number of such y values is 99 - 3 + 1 = 97. If x = 3, y must be an integer such that 3 < y < 100. Possible y values are 4, 5, ..., 99. The number of such y values is 99 - 4 + 1 = 96. ... What is the largest possible integer value for x? Since x < y < 100, the largest possible integer value for y is 99. This requires x to be at least 1 less than 99, i.e., x < 99. So, the largest possible integer value for x is 98. If x = 98, y must be an integer such that 98 < y < 100. The only possible y value is 99. The number of such y values is 1. (99 - 99 + 1 = 1) The total number of integer points inside the triangle is the sum of the number of possible y values for each x from 1 to 98. Total points = (99 - 1) + (99 - 2) + (99 - 3) + ... + (99 - 98) Total points = 98 + 97 + 96 + ... + 1 This is the sum of the first 98 positive integers. The formula for the sum of the first n positive integers is n(n+1)/2. Here, n = 98. Sum = 98 * (98 + 1) / 2 = 98 * 99 / 2 = 49 * 99. 49 * 99 = 49 * (100 - 1) = 4900 - 49 = 4851. The number of points inside the triangle with integer coordinates is 4851.

32. There are two concentric circles. The radii of the two circles are 100

There are two concentric circles. The radii of the two circles are 100 m and 110 m respectively. A wheel of radius 30 cm rolls on the smaller circle and another wheel rolls on the larger circle. After they have completed one revolution, it is found that the two wheels rolled equal number of times on their respective axes. What is the radius of the other wheel ?

31 cm
32 cm
33 cm
34 cm
This question was previously asked in
UPSC CAPF – 2016
The correct option is C) 33 cm.
When a wheel rolls on the circumference of a circle, the distance covered by the wheel’s point of contact is equal to the circumference of the larger circle it’s rolling on. This distance is also equal to the number of revolutions the wheel makes on its own axis multiplied by its own circumference.
Radius of the smaller circle (R1) = 100 m = 10000 cm.
Radius of the larger circle (R2) = 110 m = 11000 cm.
Radius of the first wheel (r1) = 30 cm.
Let N be the number of revolutions made by each wheel on its axis.
The first wheel rolls on the smaller circle (R1). The distance covered by its point of contact is the circumference of the smaller circle, which is 2πR1. This distance is also equal to N times the circumference of the first wheel, which is N * 2πr1.
So, 2πR1 = N * 2πr1
R1 = N * r1
10000 = N * 30
N = 10000 / 30 = 1000 / 3

The second wheel rolls on the larger circle (R2). Let its radius be r2. The distance covered by its point of contact is the circumference of the larger circle, which is 2πR2. This distance is also equal to N times the circumference of the second wheel, which is N * 2πr2.
So, 2πR2 = N * 2πr2
R2 = N * r2

We know R2 = 11000 cm and N = 1000/3.
11000 = (1000/3) * r2
r2 = 11000 * (3 / 1000)
r2 = 11 * 3 = 33 cm.

The radius of the other wheel is 33 cm.

33. In the diagram given below, there is a circle, a square and a triangle

In the diagram given below, there is a circle, a square and a triangle dividing the region into five disjoint bounded areas. Each of these areas are labelled with number of players belonging to that area. The circle contains cricketers, the square contains football players and the triangle contains hockey players.
Which one of the following is not correct?

Every hockey player plays football
Every cricket player plays either football or hockey
There are some hockey players who play both cricket and football
There are some football players who play neither cricket nor hockey
This question was previously asked in
UPSC CAPF – 2016
The correct option is C) There are some hockey players who play both cricket and football.
The question describes a diagram with a circle (cricketers, C), a square (football players, F), and a triangle (hockey players, H), divided into *five disjoint bounded areas*, each with a number of players. This implies that only these five specific areas within the sets contain players, and any intersection not represented by one of these five areas must contain zero players.
Let’s consider a plausible interpretation of the “five disjoint bounded areas” in a 3-set Venn diagram context. A standard 3-set Venn diagram has 7 possible regions inside the sets (C only, F only, H only, C&F only, C&H only, F&H only, C&F&H). If only five of these have players, two must be empty.
Statement C is “There are some hockey players who play both cricket and football”. This statement is true if the region representing players who play all three sports (C&F&H) has a number greater than zero. If the five disjoint areas described *do not include* the intersection of all three sets (C&F&H), then the number of players in that region is zero by implication. In this scenario, statement C would be false (“There are NO hockey players who play both cricket and football”).

Let’s test if this interpretation makes sense by assuming statement C is indeed the “not correct” one. This means C&F&H = 0. The five regions could then be, for example: C only, F only, H only, C&F only, C&H only, F&H only (this is 6, so one more must be 0). Or perhaps C only, F only, H only, C&F only, F&H only (omitting C&H only and C&F&H). Or C only, F only, H only, C&F only, C&H only (omitting F&H only and C&F&H).

If C&F&H = 0, then statement C is false. Let’s see if the other statements *could* be true under various configurations of 5 non-empty regions (where C&F&H=0):
A) “Every hockey player plays football”: Requires H only = 0 and C&H only = 0. Possible if the 5 regions are, for example, F only, C only, C&F only, F&H only, some other.
B) “Every cricket player plays either football or hockey”: Requires C only = 0. Possible.
D) “There are some football players who play neither cricket nor hockey”: Requires F only > 0. Possible.

Since statement C (C&F&H > 0) directly contradicts the implication that the region C&F&H is one of the *missing* regions among the five non-empty ones, statement C is the most likely to be the “not correct” one under a plausible interpretation of the five given areas. The wording “five disjoint bounded areas… labelled with number of players belonging to that area” strongly suggests these are the *only* regions within the shapes that contain players. If the C&F&H intersection is not one of these five, its count is 0.

34. If a place is affected by Tide at 6:00 AM Monday, normally at what tim

If a place is affected by Tide at 6:00 AM Monday, normally at what time the same place will be affected by Ebb ?

6:26 PM Monday
6:52 AM Tuesday
12:13 PM Monday
00:26 AM Tuesday
This question was previously asked in
UPSC CAPF – 2016
The correct option is C) 12:13 PM Monday.
Tides follow a predictable pattern. In most places, there are two high tides and two low tides approximately every 24 hours and 50 minutes. The time between a high tide and the subsequent low tide (Ebb) is roughly half the period between two consecutive high tides, which is about 6 hours and 12.5 minutes. Ebb tide is the phase when the sea level is falling.
Given that high tide occurs at 6:00 AM Monday.
The low tide following this high tide will occur approximately 6 hours and 12.5 minutes later.
6:00 AM + 6 hours 12.5 minutes = 12:12:30 PM Monday.
The ebb tide is the period from high tide to low tide. The question asks “at what time the same place will be affected by Ebb?”. This is slightly ambiguous, as ebb is a period. However, among the options, 12:13 PM is the closest time to the predicted low tide, which marks the *end* of the ebb phase and the start of the flood phase. The other options represent subsequent high tide times. Therefore, 12:13 PM Monday is the most plausible answer representing the transition point following the ebb phase.

35. Which of the following statements relating to the solar system is/are

Which of the following statements relating to the solar system is/are correct?
1. Venus and Uranus rotate opposite to the direction of rotation of Earth
2. Venus is the nearest planet to Earth
Select the correct answer using the code given below:

1 only
2 only
Both 1 and 2
Neither 1 nor 2
This question was previously asked in
UPSC CAPF – 2016
The correct option is C) Both 1 and 2.
Statement 1 refers to the rotation direction of Venus and Uranus compared to Earth. Statement 2 refers to the relative distance of Venus from Earth.
1. **Venus and Uranus rotate opposite to the direction of rotation of Earth:** Correct. Earth rotates counter-clockwise when viewed from above the North Pole (prograde rotation). Venus rotates clockwise (retrograde rotation). Uranus also has a unique rotation; it rotates on its side, but its rotation direction is also considered retrograde relative to its orbit.
2. **Venus is the nearest planet to Earth:** Correct, in the context of being Earth’s closest planetary neighbour at its point of closest approach. While Mercury is closer to the Sun and, on average, closer to Earth than Venus is, Venus makes the closest approach to Earth among all planets. In common parlance and many educational contexts, Venus is referred to as Earth’s nearest planet.
Both statements are considered correct in a general knowledge context like a UPSC exam.

36. Which of the following statements concerning the circum-pacific belt a

Which of the following statements concerning the circum-pacific belt are correct?
1. It is an active volcanic realm
2. It is an active seismic realm
3. It is a divergent plate boundary
4. It is prone to Tsunami
Select the correct answer using the code given below:

1 and 2 only
3 and 4 only
1, 2 and 4 only
1, 2, 3 and 4
This question was previously asked in
UPSC CAPF – 2016
The correct option is C) 1, 2 and 4 only.
The Circum-Pacific Belt, also known as the Ring of Fire, is a major area in the basin of the Pacific Ocean where a large number of earthquakes and volcanic eruptions occur. This high activity is due to the presence of numerous plate boundaries, primarily convergent ones, where tectonic plates are colliding or subducting.
Let’s evaluate each statement:
1. **It is an active volcanic realm:** Correct. The Ring of Fire contains a vast majority of the world’s active and dormant volcanoes.
2. **It is an active seismic realm:** Correct. It is the most seismically active region globally, experiencing frequent and powerful earthquakes.
3. **It is a divergent plate boundary:** Incorrect. While there are some segments of divergent boundaries (like the East Pacific Rise) and transform boundaries within or connected to the Ring of Fire, the dominant type of plate interaction responsible for the intense volcanism and seismicity in most parts of the belt is **convergent**, involving subduction zones. Divergent boundaries are typically associated with mid-ocean ridges.
4. **It is prone to Tsunami:** Correct. Tsunamis are often triggered by large underwater earthquakes, volcanic eruptions, or landslides, particularly those associated with subduction zones found along convergent plate boundaries like those prevalent in the Ring of Fire.
Therefore, statements 1, 2, and 4 are correct, while statement 3 is incorrect.

37. Which of the following are the objectives of the Khadi and Village Ind

Which of the following are the objectives of the Khadi and Village Industries Commission?
1. To provide employment in rural areas
2. To produce saleable articles
3. To create self reliance amongst people and building up a strong rural community spirit
Select the correct answer using the code given below:

1, 2 and 3
1 and 2 only
2 and 3 only
1 and 3 only
This question was previously asked in
UPSC CAPF – 2016
The correct option is A) 1, 2 and 3.
The Khadi and Village Industries Commission (KVIC) is a statutory body established by the Government of India, under the Khadi and Village Industries Commission Act, 1956. Its primary objectives are aligned with promoting and developing Khadi and village industries in rural areas.
The main objectives of KVIC are:
1. **The social objective:** Providing employment in rural areas.
2. **The economic objective:** Producing saleable articles.
3. **The wider objective:** Creating self-reliance among people and building up a strong rural community spirit.
All three statements correctly reflect the core aims and functions of the Khadi and Village Industries Commission.

38. Arrange the following varieties of silk in India in their order of dec

Arrange the following varieties of silk in India in their order of decreasing production:
1. Muga
2. Eri
3. Mulberry
4. Tasar
Select the correct answer using the code given below

3-2-4-1
3-4-2-1
2-4-1-3
2-1-4-3
This question was previously asked in
UPSC CAPF – 2016
The correct option is A) 3-2-4-1.
Silk production in India involves four main varieties: Mulberry, Eri, Tasar, and Muga. These are categorized based on the type of silkworm that produces the silk fibre. The order of decreasing production volume in India is generally Mulberry, followed by Eri, then Tasar, and finally Muga.
– **Mulberry silk** is the most common type, accounting for the vast majority (around 80-85%) of total silk produced in India. It is produced by the silkworm Bombyx mori, which feeds exclusively on mulberry leaves. It is widely cultivated across various states.
– **Eri silk** is produced by the silkworm Samia cynthia ricini, which feeds mainly on castor leaves. It is primarily concentrated in the North Eastern states, particularly Assam. It is known as the ‘poor man’s silk’ and is also called Ahimsa silk as the moth is allowed to emerge from the cocoon. It accounts for the second-largest production share (around 10-15%).
– **Tasar silk** is produced by silkworms belonging to the Antheraea species, which feed on leaves of trees like Arjun, Asan, and Sal. It is mainly produced in tribal areas of states like Jharkhand, Chhattisgarh, Odisha, West Bengal, etc. Its production share is smaller than Eri (around 5-10%).
– **Muga silk** is produced by the silkworm Antheraea assamensis, which feeds on aromatic leaves of Som and Sualu plants. This silk is unique to Assam and is known for its golden yellow colour and durability. Its production is the lowest among the four varieties due to its localized nature and specific feeding habits of the silkworm.
Thus, the decreasing order of production is Mulberry > Eri > Tasar > Muga.

39. Let a resistor having 4 ohm resistance be connected across the termina

Let a resistor having 4 ohm resistance be connected across the terminals of a 12 volt battery. Then the charge in coulomb passing through the resistor per second is:

12
4
3
0.33
This question was previously asked in
UPSC CAPF – 2016
The correct option is C) 3.
According to Ohm’s Law, the current (I) flowing through a resistor is directly proportional to the voltage (V) across it and inversely proportional to its resistance (R). The relationship is given by the formula V = IR. The current (I) is also defined as the amount of electric charge (Q) passing through a point per unit time (t), i.e., I = Q/t. The question asks for the charge passing through the resistor *per second*, which means we need to find Q when t = 1 second. From I = Q/t, we get Q = I * t. If t = 1 second, then Q = I * 1 = I. Therefore, the charge passing through the resistor per second is equal to the current flowing through it.
Given: Voltage (V) = 12 volts, Resistance (R) = 4 ohm.
Using Ohm’s Law, I = V / R = 12 V / 4 ohm = 3 Amperes.
The current is 3 Amperes, which means 3 Coulombs of charge flow through the resistor every second.
Charge passing per second = Current (I) = 3 Coulombs.

40. Which one of the following statements is not correct?

Which one of the following statements is not correct?

The earth’s magnetic field is due to the motion of metals like iron and nickel in the core of the earth
The magnetic field lines of force are widely separated near the poles of a magnet but these lines come closer to one another at other places
If the cross-sectional area of a magnetic field increases, but the flux remains the same, the flux density decreases
When the speed of a conductor moving through a magnetic field is increased, the induced voltage increases
This question was previously asked in
UPSC CAPF – 2016
Statement B is incorrect. Magnetic field lines are a visual representation of the magnetic field’s strength and direction. Where the lines are closer together, the magnetic field is stronger; where they are farther apart, the field is weaker. The magnetic field of a bar magnet is strongest at the poles. Therefore, the magnetic field lines of force are most concentrated and come closer to one another near the poles of a magnet, not widely separated. They are more widely separated away from the poles.
Understanding the properties and representation of magnetic field lines is fundamental in magnetism.
Statement A is correct: The Earth’s magnetic field is believed to be generated by the motion of molten metallic materials (primarily iron and nickel) in the Earth’s outer core, a process called the geodynamo.
Statement C is correct: Magnetic flux density (B) is defined as the magnetic flux (Φ) passing through a unit area (A) perpendicular to the direction of the flux (B = Φ/A). If the flux remains constant but the area increases, the flux density decreases.
Statement D is correct: According to Faraday’s law of electromagnetic induction, the magnitude of the induced voltage (EMF) in a conductor moving through a magnetic field is proportional to the speed at which the conductor cuts the magnetic field lines. Thus, if the speed of the conductor is increased, the induced voltage increases.