21. Planet Mars has X number of natural satellites. Element Y has atomic number X. What is the number of electrons present in an atom of element Y?
0
1
2
3
22. When looking at the radiation emitted by distant stars or galaxies, scientists see emission spectra ‘shifted’ towards the red end of the electromagnetic spectrum—the observed wavelengths are longer than expected'. Choose the correct statement about this passage.
This is known as Planck effect and infrared shift
This is known as Compton effect and red shift
This is known as Doppler effect and red shift
This is known as Compton effect and infrared shift
23. Which among the following pairs, accused for killing English officers in England, was hanged?
Madan Lal Dhingra and Udham Singh
Rajguru and Sukhdev
Khudi Ram Bose and Suryasen
Kartar Singh Sarabha and Ashfaqullah Khan
24. Consider the following Statements: Statement I: Weight of an object is minimum at poles of Earth Statement II: Mass of an object is maximum at poles of Earth Which of the above statement(s) is/are correct?
Only II
only I
Neither I nor II
Both I and II
25. Active immunity may be gained by
Natural infection
Vaccination
Toxoids
All of these