BPSC – Combined Competitive Examination · ಪ್ರಶ್ನೆ 132
Which compound is known as a glow-in-the-dark (night glowing) pigment?
ಉತ್ತರ ತೋರಿಸು ಮತ್ತು ವಿವರಣೆ
ಉತ್ತರ: (A) Europium-doped strontium aluminate
ವಿವರಣೆ
Europium (and dysprosium) doped strontium aluminate glows for hours after charging with light.
- (A) ಸರಿ
Correct: SrAl₂O₄:Eu is the main long-afterglow phosphor.
- (B) ತಪ್ಪು
Wrong: the older phosphor was copper-doped zinc sulphide, not this.
- (C) ತಪ್ಪು
Wrong: not a luminous pigment.
- (D) ತಪ್ಪು
Wrong: not a luminous pigment.