1.
There are 60 students in a class, out of them 40 are boys. At a particular day 4 girls are absent in the class. The probability of selecting a girl on that day will be
Correct Answer
A.
Explanation
Total girls in class = 60 – 40 = 20, No. of girls present in class on that day = 16
Total no. of students in class on that days = 56
P(selecting a girl on that day) =16/56 = 2/7
2.
If V is the volume of a cuboids of dimensions x, y, z, and A is its surface area, then is equal to
Correct Answer
B.
3.
In the given data 19,25,59,49,35,31,30,32,51, the median is p. A student makes a mistake of writing 25, he interchange unit and 10th place of number. Now the new median becomes q. The value of (q – p) will be
Correct Answer
C. 3
Explanation
Assending order of given data 19,25,30,31,32,35,48,51,59
median = = 5th trem = 32 = p (given)
Because student wrote 52 in the of 25 assending order of new data 19,30,31,32,35,48,51,52,59
median = =35 = q (given)
q – p = 35 – 32 = 3
4.
In the adjacent figure, PA and PB are tangents to the circle drawn from an external point P. CQD is another tangent touching the circle at Q. If PB = 10 cm and CQ = 2 cm then length of PC is
Correct Answer
C. 8 cm
Explanation
We have PB = PA =10 cm and CQ = CA = 2 cm [Q Tangent from external point to a circle are equal in
length] Now, Length of PC = PA -CA= 10 - 2= 8 cm.
5.
A hemispherical tank full of water is emptied by a pipe at the rate of liters per second. How much time will it take to empty half the tank, if its diameter is 3m
Correct Answer
C. 16.5
Explanation
The time it takes to empty half the tank can be calculated by dividing the volume of the tank by the rate at which it is being emptied. The volume of a hemisphere can be calculated using the formula V = (2/3)Ï€r^3, where r is the radius of the hemisphere. In this case, the radius is half the diameter, so it is 1.5m. The volume of the tank is therefore (2/3)Ï€(1.5^3) = 14.137m^3. Since the rate of emptying is given in liters per second, we need to convert the volume to liters by multiplying by 1000. The time it takes to empty half the tank is therefore (14.137 * 1000) / 10.32 = 1367.7 seconds, which is approximately 16.5 seconds.
6.
The loudness of sound of the bell in the bell jar experiment gradually decreases with
Correct Answer
A. Decrease in the quantity of air
Explanation
The loudness of sound of the bell in the bell jar experiment gradually decreases with decrease in the quantity of air. This is because sound waves require a medium to travel through, and air is the medium through which sound waves propagate. When the quantity of air in the bell jar decreases, there are fewer air molecules present to transmit the sound waves, resulting in a decrease in the loudness of the sound produced by the bell.
7.
Two bodies of mass 1 kg and 2 kg have equal momentum. The ratio of their kineticenergies is
Correct Answer
B. 2 : 1
Explanation
The ratio of kinetic energies is directly proportional to the ratio of masses. Since the momentum of the two bodies is equal, the ratio of their masses is 1:2. Therefore, the ratio of their kinetic energies will also be 1:2.
8.
Mechanical wave (sound wave) in a gas is
Correct Answer
B. Longitudinal
Explanation
A mechanical wave, such as a sound wave, in a gas is longitudinal. This means that the particles of the gas vibrate parallel to the direction of the wave propagation. In other words, the compressions and rarefactions of the wave occur in the same direction as the wave itself. Transverse waves, on the other hand, involve particles vibrating perpendicular to the direction of wave propagation. Since sound waves in a gas involve compression and rarefaction of the gas particles, they are classified as longitudinal waves.
9.
When an object is moved away from a convex mirror, the image
Correct Answer
D. Both (a) and (b)
Explanation
When an object is moved away from a convex mirror, the image becomes smaller and moves closer to the focus. This is because convex mirrors always produce virtual, upright, and diminished images. As the object moves away from the mirror, the reflected rays diverge, causing the image to appear smaller. Additionally, the image appears to move closer to the focus, which is the point where the reflected rays appear to converge. Therefore, both options (a) and (b) are correct.
10.
A parallel beam of light falling on the eye gets focused on the retina because of refractions at
Correct Answer
D. Various surfaces in the eye
Explanation
The correct answer is "various surfaces in the eye." When a parallel beam of light enters the eye, it undergoes refraction at multiple surfaces within the eye, including the cornea, the crystalline lens, and the vitreous humor. These surfaces help to bend the light rays and focus them onto the retina, which is the light-sensitive layer at the back of the eye. This process is necessary for clear vision and allows the eye to form a sharp image of the objects being viewed.
11.
Flower is a
Correct Answer
C. Modified shoot
Explanation
The correct answer is modified shoot. A flower is a modified shoot because it is derived from a shoot system of a plant. Shoots are the above-ground parts of a plant that include stems, leaves, and flowers. Flowers are specialized shoots that are modified for reproductive purposes, containing the reproductive organs of the plant. They have modified leaves called petals, modified stems called the stalk or peduncle, and modified reproductive structures such as the pistil and stamen. Flowers play a crucial role in plant reproduction by attracting pollinators and facilitating the transfer of pollen.
12.
Mycelium and hyphae are found in
Correct Answer
C. Fungi
Explanation
Mycelium and hyphae are found in fungi. Fungi are a group of organisms that include molds, mushrooms, and yeasts. Mycelium refers to the mass of thread-like structures called hyphae that make up the main body of a fungus. These structures are responsible for absorbing nutrients and providing support for the fungus. Therefore, the correct answer is fungi, as mycelium and hyphae are characteristic features of this group of organisms.
13.
Which of the following is an aquatic adaptation?
Correct Answer
D. Presence of fins
Explanation
The presence of fins is an aquatic adaptation because fins are specialized appendages that allow aquatic animals to navigate and move efficiently through water. Fins provide stability, balance, and maneuverability in water, enabling animals to swim and control their movements. This adaptation is commonly found in fish and other aquatic organisms, allowing them to thrive in their aquatic habitats.
14.
Which of the following is absent in dicots?
Correct Answer
D. Parallel venation in leaves
Explanation
Dicots are a type of flowering plants that have two cotyledons in their seeds, cambium in their vascular bundles, and undergo secondary growth. However, parallel venation in leaves is absent in dicots. Instead, dicots have reticulate venation, where the veins of the leaves form a network-like pattern. This helps to differentiate dicots from monocots, which have parallel venation in their leaves.
15.
The adaptation of earthworm is
Correct Answer
B. Burrowing
Explanation
The correct answer is burrowing. Earthworms are adapted for burrowing as they have a long, cylindrical body with a slimy skin that allows them to move through the soil easily. They also have bristles called setae on their body, which help them grip the soil and move forward. Additionally, earthworms have a specialized muscular organ called a clitellum that helps them create tunnels in the soil as they burrow. These adaptations enable earthworms to live and thrive in underground environments.
16.
Which one of the following statement is correct?
Correct Answer
A. Soap solution turns red litmus blue.
Explanation
Soap solution turns red litmus blue because soap is a basic substance. Litmus paper is a pH indicator that turns red in acidic solutions and blue in basic solutions. Therefore, when soap solution comes into contact with red litmus paper, it will turn the paper blue, indicating its basic nature.
17.
Which one of the following compounds does not contain a multiple bond?
Correct Answer
A.
Explanation
Benzene does not contain a multiple bond. Benzene is a cyclic compound consisting of six carbon atoms and six hydrogen atoms. It is classified as an aromatic compound and has a unique structure known as a hexagonal ring. Each carbon atom in the benzene ring is bonded to two other carbon atoms and one hydrogen atom, resulting in a total of six sigma bonds. There are no double or triple bonds present in the structure of benzene. Therefore, the correct answer is benzene.
18.
Which one of the following salts is not present is hard water?
Correct Answer
D. Sodium chloride
Explanation
Sodium chloride is not present in hard water. Hard water is characterized by high levels of calcium and magnesium ions, which form insoluble salts with carbonate and sulfate ions. Calcium sulfate and magnesium bicarbonate are examples of such salts that are commonly found in hard water. Calcium chloride, although not as common as the other salts, can also be present in hard water. However, sodium chloride does not contribute to water hardness and is not typically found in hard water.
19.
Which of the following hydrocarbon shows isomerism?
Correct Answer
D.
20.
Which of the following has the shortest carbon-carbon bond?
Correct Answer
C.