- AThree
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Which of the following is accompanied by the characteristic X-ray emission
| (a) α - particle emission | (b) Electron emission |
| (c) Positron emission | (d) K–electron capture |
A 20F capacitor is charged to 5V and isolated. It is then connected in parallel with an uncharged 30F capacitor. The decrease in the energy of the system will be
|
(a) 25 J |
(b) 200 J |
(c) 125 J |
(d) 150 J |
A man can see the object between 15 cm and 30 cm. He uses the lens to see the far objects. Then due to the lens used, the near point will be at
|
(a) |
(b) 30 cm |
(c) 15 cm |
(d) |
The cause of the potential barrier in a P-N diode is
|
(a) Depletion of positive charges near the junction |
|
(b) Concentration of positive charges near the junction |
|
(c) Depletion of negative charges near the junction |
|
(d) Concentration of positive and negative charges near the junction |
White light is incident on the interface of glass and air as shown in the figure. If green light is just totally internally reflected then the emerging ray in air contains

|
(a) Yellow, orange, red |
(b) Violet, indigo, blue |
|
(c) All colours |
(d) All colours except green |