To determine which colors will eject electrons when they strike sodium, we need to compare their respective frequencies to the frequency threshold of 5.7 × 10¹⁴ Hz.
The frequencies for the given colors are:
- Red: 4.3 × 10¹⁴ Hz
- Orange: 4.8 × 10¹⁴ Hz
- Green: 5.5 × 10¹⁴ Hz
- Violet: 7.5 × 10¹⁴ Hz
We'll check each color to see if its frequency is greater than or equal to the threshold frequency of 5.7 × 10¹⁴ Hz.
1. Red: [tex]\( 4.3 \times 10^{14} \text{ Hz} \)[/tex]
- Red's frequency (4.3 × 10¹⁴ Hz) is less than the threshold (5.7 × 10¹⁴ Hz).
- Therefore, red will not eject electrons.
2. Orange: [tex]\( 4.8 \times 10^{14} \text{ Hz} \)[/tex]
- Orange's frequency (4.8 × 10¹⁴ Hz) is less than the threshold (5.7 × 10¹⁴ Hz).
- Therefore, orange will not eject electrons.
3. Green: [tex]\( 5.5 \times 10^{14} \text{ Hz} \)[/tex]
- Green's frequency (5.5 × 10¹⁴ Hz) is less than the threshold (5.7 × 10¹⁴ Hz).
- Therefore, green will not eject electrons.
4. Violet: [tex]\( 7.5 \times 10^{14} \text{ Hz} \)[/tex]
- Violet's frequency (7.5 × 10¹⁴ Hz) is greater than the threshold (5.7 × 10¹⁴ Hz).
- Therefore, violet will eject electrons.
Thus, the only color that will eject electrons when striking sodium is violet.
Therefore, the correct answer is:
Violet only
