As the electric current in a lightbulb is slowly increased, the filament glows more and more brightly. why does this happen?

Explanation:

As the current in a light bulb increases gradually, the filament shines more and more brightly. This occurs as the more current passes through a light bulb, the brighter it glows.  

The more the current, the more will be the power, here the power determines the brightness of a bulb. More the current, the more will be the dissipation of power in the form of light and heat. If the current enhances then the brightness will also get an increase.  

the answer to your question is c.

if you read the house of usher you should know that the house was haunted

assuming that your periodic table has eighteen columns, you should highlight   the four elements in the third column from the left of the table.

neutral atoms of elements after calcium contain d electrons. the energy of d orbitals of a particular main shell lies between the energy of the s and p orbitals of the next main shell. for example, electrons in the have energy higher than those in the orbital while lower than those of the orbital.

by the aufbau principle, electrons fill orbitals one at a time, starting from those of the lowest energy. the orbital is therefore filled right after orbitals and before orbitals.  

potassium has electron configuration and calcium . the s orbital of a main shell holds a maximum of two electrons. the next element would thus have the electron configuration and satisfy the requirements.

a neutral atom of the element contains three electrons on top of the most recent noble gas element. it should thus be placed in the third column of the periodic table. both scandium and yttrium would satisfy the conditions. an aufbau diagram indicates that the 4f orbital is filled before the 5d. however, it appears that exceptions exists for both lanthanum and actinium. neutral atoms of the two d-block elements also demonstrate the and should be highlighted as well.