Mix Test - 9

The position of d-block elements is in between s-block and p-block elements in the periodic table. These d-block elements are called transition elements because they exhibit transitional behaviour between s-block and p-block elements. 

Transition metals are d-block elements with valence shell configuration ns² (n-1) d^(1-10).

The transition metals and their ions easily coordinate to a number of negative ions or neutral molecules having lone pairs of electrons to form complexes.

The reason for this is the small size and high nuclear charge of these metals and the availability of vacant d-orbitals of suitable energy to accommodate lone pairs of electrons donated by the ligands.

The cations of the d-block elements have a strong tendency to form complexes with certain molecules or ions called ligands. 

So, transition metals form complexes due to their Small size, Available d orbital and Large ionic charge.

Hence, the correct option is (D).

The virus which infects the bacteria is called bacteriophage.

A bacteriophage is generally a double-stranded DNA virus. In QB - bacteriophage - ss RNA is present. In ϕ X 174 - bacteriophage - ss DNA is present. A bacteriophage is of two types- Non-infective phages and infective phage.

Hence, the correct option is (B).

Given - The biconvex lens of glass having refractive index \(1.47\)

The equation of lens makers formula is given by 

\(\frac{1}{f}=\left(\frac{\mu_{l}}{\mu_{c}}-1\right)\left(\frac{1}{R_{1}}-\frac{1}{R_{2}}\right)\)  ....(1)

Where \(\mu_{\mathrm{l}}=\) refractive index of liquid and \(\mu_{\mathrm{c}}=\) refractive index of the convex lens

According to question, when a biconvex lens is dipped in a liquid, then it acts as a plane sheet of glass, therefore \(f=\infty\)

When a biconvex lens act as plane sheet then, it's focal length f=0

\(\Rightarrow \frac{1}{f}=0\)

Then equation (1) becomes

\(\Rightarrow 0=\left(\frac{\mu_{l}}{\mu_{c}}-1\right)\left(\frac{1}{R_{1}}-\frac{1}{R_{2}}\right)\)

\(\Rightarrow 0=\left(\frac{\mu_{l}}{\mu_{c}}-1\right)\)

\(\Rightarrow \mu_{l}=\mu_{c}\)

The Refractive index of liquid  = Refractive index  of the convex lens

Hence, the correct option is (B).

In humans and most mammals and birds, the iris (plural: irides or irises) is a thin, annular structure in the eye, responsible for controlling the diameter and size of the pupil and thus the amount of light reaching the retina. Eye color is defined by that of the iris.

Hence, the correct option is (C).

The Bartholin's glands are located on each side of the vagina's opening. They secrete a fluid that helps lubricate the vagina. Sometimes the ducts of these glands become obstructed and fluid backs up, forming a cyst.

Hence, the correct option is (B).

The correct answer is The Speed of sound decreases from Solid to Liquid to Gaseous state.

About Speed of Sound in different media:

The Speed of Sound is defined as is the (distance traveled per unit time) by any sound. It is the Dynamic propagation of sound waves that depends on some of the characteristics of the medium through which the propagation of sound takes place. The Speed of sound is used for the speed of sound waves in an elastic medium.

• Some of the factors which affect the Speed of Sound are as follows:
• The speed of the sound in a medium depends on the temperature of the medium because it is directly proportional to each other if (temperature increases, Speed of sound increases).
• It depends upon the density of the medium When the medium is dense, the molecules in the medium are closely packed to each other which means that the force required by the molecules is more vibration required. Hence we can see that(The speed of sound decreases when we go from solid to the gaseous state. In any medium, as we increase the temperature the speed of sound increases).

For example, the speed of sound in air is 331 m s^–1 at 0ºC and 344 m s^–1 at 22ºC.

Therefore, it is proved that the speed of sound decreases when we go from Solid to Liquid to Gaseous state.

Hence, the correct option is (A).

During lightning, the process happening in environment is Nitrogen fixation.

Lighting causes nitrogen fixation. Also when it strikes ground, it causes earthing. Lightning is an electrical discharge caused by imbalances between storm clouds and the ground, or within the clouds themselves. Most lightning occurs within the clouds. This heat causes surrounding air to rapidly expand and vibrate, which creates the pealing thunder we hear a short time after seeing a lightning flash.

Hence, the correct option is (A).

Manas Tiger Reserve is situated in the Himalayan foothills of  Assam.

 Manas Tiger Reserve is a UNESCO World Heritage Site. Manas National Park is a national park, a tiger reserve, an elephant reserve, and a biosphere reserve. Manas National Park gets its name from the River Manas, which flows through the reserve and is also the major tributary of the Brahmaputra River. 

Hence, the correct option is (C).

Melamine is not thermoplastics, it is thermosetting plastic. Acrylic, polyethylene and polystyrene are thermoplastic.

A thermoplastic is a material, usually a plastic polymer, which becomes more soft when heated and hard when cooled. When thermoplastics are heated to their melting point, they melt to a liquid. They freeze to a glassy state when cooled below their glass transition temperature.

Hence, the correct option is (D).

Rocket works on the principle of conservation of Momentum. 

Since the energy of the rocket's fuel converts into heat energy that propels the rocket. So the energy of the rocket only is not conserved. The energy of the rocket and the surrounding will be conserved but not of the rocket.

Hence, the correct option is (A).

Given:

Speed of light in medium 1  \(\left(\mathrm{v}_{1}\right)=1.5 \times 10^{8} \mathrm{~m} / \mathrm{s}\)

Speed of light in medium 2 \(\left(\mathrm{v}_{2}\right)=2 \times 10^{8} \mathrm{~m} / \mathrm{s}\)

Critical Angle: When the angle of refraction is \(90^{\circ}\), then the angle of incidence at that point is known as the critical angle \(({i}_{c})\). In this case:

\(i_{c}=\sin ^{-1}\left(\frac{v_{1}}{v_{2}}\right)\)

\(i_{c}=\sin ^{-1}\left(\frac{1.5 \times 10^{8}}{2 \times 10^{8}}\right)\)

\(\Rightarrow i_{c}=\sin ^{-1}\left(\frac{3}{4}\right)\)

So, when the angle of incidence is greater than or equal to the critical angle ( \(\sin ^{-1}\left(\frac{3}{4}\right)\) ), the total internal reflection will happen.

Hence, the correct option is (C).

Harvesting is a task of cutting of crop after it is mature.

The cutting and gathering of the crop after it is mature are called harvesting. The process of gathering the full-grown crops is known as harvesting and the process of cutting pulse and grain to harvest is known as reaping.

Hence, the correct option is (A).

The property of a body, by virtue of which it tends to regain its original size and shape when the applied force is removed, is known as elasticity.

Examples: Rubber bands and elastic and other stretchy materials display elasticity.

Hence, the correct option is (A).

Given:

Frequency of sound wave $=220$ Hz

Speed of sound wave $=440$ m/s

Calculate wavelength.

We know that,

Speed $=$ Wavelength $\times$ Frequency

$\mathrm{v}=\mathrm{\lambda \nu }$

$440=$ Wavelength $\times 220$

Wavelength = $\frac{440}{220}$

Wavelength $=2$

Therefore, the wavelength of the sound wave $=2$ meters.

Hence, the correct option is (A).

The epidermis is the protective outer layer of clonally related cells covering all plant organs.

It is made up of cellulose, hemicelluloses, and pectin. Regulates and controls the direction of cell growth. Providing strength, structural support, and maintaining the shape of the cell. It supports the entry of smaller molecules moving freely.

Hence, the correct option is (A).