PS-2

A student is researching the effects of electromagnetic radiation on human skin for a written report. The student studies by reading a document posted on a university website, which states that individual photons with sufficient energy can ionize molecules within certain skin cells. The student also reads a post on a personal Internet blog that claims all light can ionize molecules in skin cells. The student wants to know which source is more reliable and should be cited in the written report. Select words from the lists to complete the sentence. The [dropdown options: document from the university website; blog post] is more likely to be reliable because the information [dropdown options: is consistent with; contradicts] established scientific knowledge.

A simplified version of part of the periodic table is shown. According to their positions in the periodic table, which elements are most likely to combine with Li and Na in a one-to-one ratio to form ionic compounds?

• Be and Mg

• O and S

• F and Cl

• Ne and Ar

The figure shows a ball held at rest at the top of a hill of height h = 200 m. The potential energy of the ball-Earth system is 100 J. The ball is then released and rolls down the hill. What is the kinetic energy of the ball when it is at height h = 100 m?

• 0 J

• 50 J

• 80 J

• 100 J

Students were investigating the properties of electromagnets. They set up an investigation using a D-cell battery, an iron nail, and a length of wire. Their setup is shown. Students tested their electromagnets by wrapping the iron nail with different numbers of coils of the wire and determined the strength of the magnet by recording the number of paper clips the magnet attracted. The students concluded that the more coils of wire wrapped around the nail, the greater the strength of the electromagnet. What other design could the students implement to increase the strength of the magnetic field?

• use a shorter iron nail and repeat the experiment using the same number of coils of wire

• connect more than one battery in series to be able to pick up more metal objects

• use a nail made of a different metal than iron

• change the direction of the electrical current

A model for the decomposition of H₂O₂ into H₂O and O₂ is shown. The reaction releases 196 kJ of energy to the surroundings as it occurs. Based on this information, which statement is best supported by the model?

• The average O–H bond energy in H₂O is lower than the average O–H bond energy in H₂O₂ because energy is needed for the reaction to occur.

• The total bond energies of the product molecules is equal to the total bond energies of the reactant molecules because the number and types of atoms are equal.

• Energy is transferred to the surroundings when H₂O₂ decomposes because there are more bonds in the reactant molecules than the product molecules.

• The average O=O bond energy is higher than the average O–O bond energy because more energy is released when a O=O bond forms than the energy absorbed when O–O bonds break.

Momentum of purple number four ball after the collision:

• 0 kg • m/s

• 0.5 kg • m/s

• 0.8 kg • m/s

• 20 kg • m/s

A student is investigating the relationship between force and acceleration. The student pulls an object along a frictionless surface for 13 different trials. During each trial the student pulls the object for a certain length of time using a different force. The graph shows the data. Given the results of the trials, which is the best prediction of the acceleration the same object would have if the student conducted a trial with a force of 25 newtons (N)?

• 6.75 m/s²

• 12.5 m/s²

• 25.0 m/s²

• 50.0 m/s²

Select the correct phrases from the menus to explain why the two images look different. The man's hand can be seen in the image on the right because:

• infrared cameras ignore the color black

• only living things emit significant infrared radiation

• the bag is cooler than the hand and transparent to infrared

Tags

NGSS.HS-PS3-4

NGSS.HS-PS4-5

The man's eyes cannot be seen in the image on the right because:

• his glasses are made to look like sunglasses under certain lighting

• the infrared radiation emitted by his eyes does not pass through glass

• the area around his eyes is fairly cold and does not emit much infrared

Tags

NGSS.HS-PS4-4

Energy from the Sun is first captured by the scooter's

• RBS.

• motor.

• batteries.

• solar panels.