10 QA on electromagnetic spectrum | Learn Physics

10 Question-Answer on electromagnetic spectrum

1.       The wavelength of X-rays is of the order of:

(a)    1 metre

(b)   1 cm

(c)    1 micron

(d)   1 angstrom

Ans: ( d)

2.       Which of the following is the largest wave?

(a)    X-rays

(b)   ϒ – rays

(c)    Microwaves

(d)   Radio waves

Ans : (d)

3.       In which of the following, emission of electrons does not take place

(a)    Thermionic emission

(b)   X-ray emission

(c)    Photoelectric emission

(d)   Secondary emission

Ans: ( b)

4.       Molybedenum is used as a target element for the production of X-xrays because it is

(a)    Light and can easily deflect electrons

(b)   Light and can absorb electrons

(c)    A heavy element with a high melting point

(d)   An element heaving high thermal conductivity

Ans: (c)

5.       Which of the following electromagnetic waves have the largest wavelength

(a)    Heat waves

(b)   Light waves

(c)    Radio waves

(d)   Microwaves

Ans: ( c)

6.       Which of the following is of shortest wave-length?

(a)     X-rays

(b)   Y-rays

(c)    Microwaves

(d)   Radio waves

Ans; (b)

7.       Radio waves do not penetrate in the band of

(a)    Ionosphere

(b)   Mesosphere

(c)    Troposphere

(d)   Stratosphere

Ans: (a)

8.       The wavelength of X-rays lies between

(a)    Maximum to finite  limits

(b)   Minimum to certain limits

(c)    Minimum to infinite limits

(d)   Infinite to finite limits

Ans: ( b)

9.       The penetrating  power of X-rays increases with the increase in its

(a)    Velocity

(b)   Intensity

(c)    Frequency

(d)   Wavelength

Ans:  (c)

10.   Hydrogen atom does not emit X-rays because

(a)    It has single electron

(b)   It has no neutron

(c)    It has single neutron

(d)   Its energy levels are too close to each other

Ans: ( a)