A man's face is 30 cm in front of a concave spherical shaving mirror. If the image is erect and 1.5 times as large as his face, what is the radius of curvature of the mirror?
A) 40 cm
B) 60 cm
C) 100 cm
D) 140 cm
E) 180 cm
Answer: E
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Electric field lines
A) are closer together the stronger the field. B) start on negative charges and end on positive charges. C) were invented by Isaac Newton. D) are perpendicular to the lines of force. E) were discovered by Franklin.
Vector = 4.00 m points eastward and vector = 3.00 m points northward. The resultant vector + is given by
A) 5.00 m at an angle 71.6° north of east. B) 5.00 m at an angle 36.9° north of east. C) 5.00 m at an angle 53.1° north of east. D) 5.00 m at an angle 18.4° north of east. E) 5.00 m at an angle 26.6° north of east.
A test charge of +3 ?C is at a point P where the electric field due to other charges is directed to the right and has a magnitude of 4 x 106 N/C. If the test charge is replaced with a –3 ?C charge, the electric field at P
1.has the same magnitude as before, but changes direction. 2.increases in magnitude and changes direction. 3.remains the same. 4.decreases in magnitude and changes direction.
During the time that latent heat is involved in a change of state:
A. the temperature does not change B. the substance always expands C. a chemical reaction takes place D. molecular activity remains constant E. kinetic energy changes into potential energy