NEET Practice Questions (MCQs) with Answers & Solutions

The text states, 'In Fig. 10.7(c) a plane wave is incident on a concave mirror and on reflection we have a spherical wave converging to the focal point F.'

The text notes, 'it predicted that on refraction if the wave bends towards the normal then the speed of light would be less in the second medium. This is in contradiction to the prediction made by using the corpuscular model of light. It was much later confirmed by experiments where it was shown that the speed of light in water is less than the speed in air confirming the prediction of the wave model; Foucault carried out this experiment in 1850.'

The text provides Snell's Law as '$n_1 \sin i = n_2 \sin r$ (10.6)'.

The text explains, 'Clearly, since the speed of light waves is less in glass, the lower portion of the incoming wavefront (which travels through the greatest thickness of glass) will get delayed resulting in a tilt in the emerging wavefront...'

The discussion concludes, 'From the above discussion it follows that the total time taken from a point on the object to the corresponding point on the image is the same measured along any ray. For example, when a convex lens focuses light to form a real image, although the ray going through the centre traverses...'

The text states, 'We now consider refraction of a plane wave at a rarer medium, i.e., $v_2 > v_1$. Proceeding in an exactly similar manner we can construct a refracted wavefront as shown in Fig. 10.5. The angle of refraction will now be greater than angle of incidence...'

The context explains, 'In order to construct the reflected wavefront we draw a sphere of radius $vt$ from the point A as shown in Fig. 10.6. Let CE represent the tangent plane drawn from the point C to this sphere. Obviously AE = BC = $vt$'. Therefore, AE and BC are equal.

The term 'Osteichthyes' literally translates to 'bony fish,' indicating an endoskeleton made of bone. The NCERT text implicitly supports this by contrasting them with Chondrichthyes, which have a cartilaginous endoskeleton.

The NCERT text states, 'Besides the basic chordate characters, vertebrates have a ventral muscular heart with two, three or four chambers, kidneys for excretion and osmoregulation and paired appendages which may be fins or limbs.' This directly indicates kidneys for excretion and osmoregulation in vertebrates.

The NCERT text states, 'Gnathostomata has two super classes, Pisces and Tetrapoda. Classes Chondrichthyes and Osteichthyes bear fins for locomotion and are grouped under Pisces.' This confirms that fins for locomotion are a common characteristic of all members grouped under Pisces, which includes both Chondrichthyes and Osteichthyes.