Light of a given wavelength is used to illuminate the surfacce of a metal, however, no photoelectrons are emitted. in order to cause electrons to be ejected from the surface of this metal you shoulda. use light of the same wavelength but increase its intensity. b. use light of a shorter wavelength. c. use light of the same wavelength but decrease its intensity. d. use light of a longer wavelength.

B. use light of a shorter wavelength.

Explanation:

We know that

h= plank's constant

c= speed of light

λ= wavelength of the incident light

so, in order to have sufficient energy for for the emission of electron, the incident's radiation must have λ small enough.

B. use light of a shorter wavelength.

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1.            c. is smaller

2.            d) concrete operational

3.            b) interaction with the environment – the children interact with their environment can them learn more.

4.            a) parents who reason openly with children can limit a child’s cognitive ability.