Light of wavelength 0.50 m illuminates a soap film (n = 1.33). What is the minimum thickness of film that will give an interference when the light is incident normally on it?
What will be an ideal response?
Question 2A rectangular loop of wire of width 10 cm and length 20 cm has a current of 2.5 A flowing through it. Two sides of the loop are oriented parallel to a uniform magnetic field of strength 0.037 T,
the other two sides being perpendicular to the magnetic field. The magnitude of the torque on the loop is
A) 0.0093 mN.
B) 0.025 mN.
C) 0.050 mN.
D) 0.0019 mN.
E) 0.038 mN.
Question 3The Voyager probes carry what kind of physical time capsule?
A) a small engraved plaque
B) a gold-plated record containing pictures, multilingual greetings and music
C) a DVD containing pictures
D) these probes do not carry a physical time capsule
Question 4In a He-Ne laser, the actual emission line at 632.8 nm comes from a jump down in what atom(s)?
A) neon
B) helium
C) helium and neon
D) oxygen
E) hydrogen
Question 5If the ac peak current through a 100 ohm resistor is 1.7 A, the peak voltage across this resistor is
A) 289 V.
B) 110 V.
C) 170 V.
D) 210 V.
E) 120 V.
Question 6A slide projector is designed with its lens 6.0 m from the screen. The projected image is 1.5 m square of a slide object 2.5 cm square.
(a) What is the object distance from the lens?
(b) What should be the lens focal length?
(c) What is the lens POWER?
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