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A convex lens A of focal length $20\text{ cm}$ and a concave lens B of focal length $5\text{ cm}$ are kept along the same axis with the distance $d$ between them. If a parallel beam of light falling on A leaves B as a parallel beam, then distance $d$ in cm will be:
Which evolutionary phenomenon is depicted by the sketch given in figure?
In a species, the weight of a newborn ranges from 2 to 5 kg. 97% of the newborns with an average weight between 3 to 3.3 kg survive whereas 99% of the infants born with weights from 2 to 2.5 kg or 4.5 kg to 5 kg die. Which type of selection process is taking place?
Select the correct statement regarding the mutation theory of evolution:
Select the favourable conditions required for the formation of oxyhaemoglobin at the alveoli.
Given below are two statements: Statement A: A Zener diode is connected in reverse bias when used as a voltage regulator. Statement B: The potential barrier of p-n junction lies between 0.2 V to 0.3 V.
If $x = 5 \sin(\pi t + \frac{\pi}{3}) \text{ m}$ represents the motion of a particle executing simple harmonic motion, the amplitude and time period of motion, respectively are:
Which solution is part of Fehling solution 'A' (used in tests for reducing sugars and aldehydes)?
The concept of chemical evolution is based on:
According to Hugo de Vries, the mechanism of evolution is:
A population of a species invades a new area. Which of the following condition will lead to adaptive radiation?
A biconvex lens of refractive index 1.5, has a radius of curvature of magnitude $20\text{ cm}$. Which one of the following options describes best the image formed of an object of height $2\text{ cm}$ placed $30\text{ cm}$ from the lens?
A ray of light is incident on a $60^{\circ}$ prism at the minimum deviation position. The angle of refraction at the first face (i.e., incident face) of the prism is:
The similarity of bone structure in the forelimbs of many vertebrates is an example of:
The extinct human who lived 1,00,000 to 40,000 years ago, in Europe, Asia, and parts of Africa, with short stature, heavy eyebrows, retreating foreheads, large jaws with heavy teeth, stocky bodies, a lumbering gait, and stooped posture was:
In a population of 1000 individuals, 360 belong to genotype AA, 480 to Aa and the remaining 160 to aa. Based on this data, the frequency of allele A in the population is:
Which of the following had the smallest brain capacity?
A converging beam of rays is incident on a diverging lens. Having passed though the lens the rays intersect at a point $15\text{ cm}$ from the lens on the opposite side. If the lens is removed the point where the rays meet will move $5\text{ cm}$ closer to the lens. The focal length of the lens is:
Among the following, the most characteristic oxidation states for lead and tin are, respectively:
From his experiments, S.L. Miller produced amino acids by mixing which of the following in a closed flask?