NEET Practice Questions (MCQs) with Answers & Solutions

The NCERT text highlights, 'Mechanical support is much less of a problem since a mirror weighs much less than a lens of equivalent optical quality, and can be supported over its entire back surface, not just over its rim.'

The NCERT diagram (Fig. 9.26) and description explain: 'One such arrangement using a convex secondary mirror to focus the incident light, which now passes through a hole in the objective primary mirror, is shown in Fig. 9.26. This is known as a Cassegrain telescope, after its inventor.'

The NCERT states, 'The largest reflecting telescopes in the world are the pair of Keck telescopes in Hawaii, USA, with a reflector of 10 metre in diameter.'

The NCERT text specifies, 'Terrestrial telescopes have, in addition, a pair of inverting lenses to make the final image erect.'

The angular magnification (m) for a telescope is given by $m = f_o / f_e$. Given $f_o = 1.5$ m $= 150$ cm and $f_e = 1.0$ cm. So, $m = 150 ext{ cm} / 1.0 ext{ cm} = 150$. This is directly from practice problem 9.14 (a) in the NCERT.

The NCERT text states regarding the Cassegrain telescope, 'It has the advantages of a large focal length in a short telescope.'

The NCERT text explains, 'The former [light gathering power] clearly depends on the area of the objective. With larger diameters, fainter objects can be observed.'

The context states: 'Splitting of water molecules is associated with PS II resulting in the release of O2, protons and transfer of electrons to PS II.' This release of protons inside the thylakoid lumen directly contributes to the proton gradient.

The text mentions: 'During this process a proton gradient is created across the membrane of the thylakoid.' and 'The breakdown of the protons gradient due to movement through the F0 part of the ATPase enzyme releases enough energy for synthesis of ATP.' This implies protons accumulate inside the thylakoid lumen.

The context explicitly states: 'The breakdown of the protons gradient due to movement through the F0 part of the ATPase enzyme releases enough energy for synthesis of ATP.'