Question

1:-do we need to learn determination of exact focal length for ICSE boards examination 2019.&
2:- do we need to learn frequency and wavelength of different electromagnetic spectrum for ICSE board examination 2019.
*I will market brainliest if you answer correctly*

Answer 1

1. yes

2. we are supposed to learn only wavelengths

Answer 2

yes u need to learn focal length ..
bt u can learn the attachment for spectrum