I am going through 'All About Particles', and came across the following two sentences:
なぜ彼がそんなことをやったか、わかりません。
どうして彼女がそんなつまらない本を読んでいるのか、不思議です。
What is the difference between using か in the first one and のか in the second? I have searched online, and のか seems to carry a sense of 'questioning the former'. Does that mean I could also use のか in the first sentence?