A normal eye is not able to see objects closer than 25cm because:
Explanation:
The ciliary muscles adjust the focal length to form an image on the retina, but the muscles cannot be strained beyond a limit. Hence, if the object is brought too close to the eye, the focal length cannot be adjusted to form the image on the retina.
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A neutron with velocity V strikes a stationary deuterium atom, its kinetic energy changes by a factor of
|
(a) |
(b) |
(c) |
(d) None of these |
Two coherent sources of different intensities send waves which interfere. The ratio of maximum intensity to the minimum intensity is 25. The intensities of the sources are in the ratio
|
(a) 25 : 1 |
(b) 5 : 1 |
(c) 9 : 4 |
(d) 25 : 16 |
Two stars P and Q are observed at night. Star P appears reddish while, star Q is white. From this we conclude
|
(a) Temperature of Q is higher than that of P |
|
(b) Temperature of Q is lower than that of P |
|
(c) Star Q is at the same distance at that of star P |
|
(d) Star P is farther than star Q |
Consider an electron in the nth orbit of a hydrogen atom in the Bohr model. The circumference of the orbit can be expressed in terms of the de Broglie wavelength λ of that electron as
|
(a) (0.259)n λ |
(b) |
(c) (13.6) λ |
(d) n λ |
$\text{F = Mg}$
$\text{F}=\mu\text{Mg}$
$\text{Mg}\leq\text{F}\leq\text{Mg}\sqrt{1+\mu^2}$
$\text{Mg}\geq\text{F}\geq\text{Mg}\sqrt{1-\mu^2}.$
A positively charged ball hangs from a silk thread. We put a positive test charge 
at a point and measure F/, then it can be predicted that the electric field strength E
|
(a) |
(b) |
(c) |
(d) Cannot be estimated |
