Scalars and vectors — practice question

For which quantity would the magnitude give a reasonable estimate?

• Afrequency of a radio wave: $500\ \text{pHz}$
• Bmass of an atom: $500\ \mu\text{g}$
• Cthe Young modulus of a metal: $500\ \text{kPa}$
• Dwavelength of green light: $500\ \text{nm}$