What affects the apparent brightness of a star

A star may form a black hole once it cannot?

How many lines/cm should be present in a diffraction grating to produce the first bright fringe at an angle of 4o when yellow light of wavelength 580 nm passes through it?

An oil drop with a mass of 8.3 grams and a charge of + 2.2 mC is floating 7.68 meters above a positively charged floor. What is the magnitude of the charge on the floor?

What two statements are true about energy transformations

Which of the following best represent positive self-talk A. "I'm making progress". B. "its just not my day". "I've tried. I just can't do it". D. "nothing ever goes right".

A 0.0663 kg ingot of metal is heated to 241◦C and then is dropped into a beaker containing 0.395 kg of water initially at 25◦C. If the final equilibrium state of the mixed system is 27.4 ◦C, find the specific heat of the metal.

What does it mean when we say an atom has decayed?

If the mass of a material is 77 grams and the volume of the material is 19 cm3, what would the density of the material be

A bicyclist is in a 50-km race. She says she had an average velocity of 35. What is missing in the cyclist's velocity? A. units only B. units and distance C. direction only D. units and direction

Which one of the following statements concerning emf is true? A) Emf is the work done in moving the current from one terminal to the other of an emf device.