# Grile Materiale

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Erykas77
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Questions: 205 | Attempts: 2,824  Settings  • 1.

### 1. Cantitatea de substanţă existentă într-un corp determina:

• A.

A) masa corpului;

• B.

B) greutatea corpului;

• C.

C) volumul real al corpului;

• D.

D) volumul aparent al corpului;

• E.

A. A) masa corpului;
Explanation
The correct answer is a) masa corpului. The quantity of substance existing in a body determines its mass. Mass is a measure of the amount of matter an object contains, and it is independent of the object's location or gravitational pull. Therefore, the quantity of substance present in a body directly affects its mass.

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• 2.

### 2. Forţa cu care un corp este atras de pămant datorită acceleraţiei gravitaţionale determină:

• A.

A) masa corpului;

• B.

B) greutatea corpului;

• C.

C) volumul real al corpului;

• D.

D) volumul aparent al corpului;

• E.

D) volumul aparent al corpului;

B. B) greutatea corpului;
Explanation
The force with which a body is attracted to the Earth due to gravitational acceleration determines its weight. Weight is a measure of the force of gravity acting on an object, and it is dependent on the mass of the object and the acceleration due to gravity. The greater the mass of an object, the greater its weight will be. Similarly, the greater the acceleration due to gravity, the greater the weight of the object will be. Therefore, the correct answer is b) greutatea corpului (the weight of the body).

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• 3.

### 3. Spaţiul ocupat de un corp poros in starea sa normală, determină:

• A.

A) masa corpului;

• B.

B) greutatea corpului;

• C.

C) volumul real al corpului;

• D.

D) volumul aparent al corpului;

• E.

D. D) volumul aparent al corpului;
Explanation
The correct answer is d) volumul aparent al corpului. This is because the space occupied by a porous body in its normal state refers to the volume that is observed or measured when the body is immersed in a fluid. This volume includes both the actual volume of the solid material as well as the volume of the empty spaces or pores within the body. Therefore, it is referred to as the apparent volume of the body.

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• 4.

### 4. Spaţiul ocupat de materialele aflate în vrac, determină:

• A.

A) masa corpului;

• B.

B) greutatea corpului;

• C.

C) volumul real al corpului;

• D.

D) volumul aparent al corpului;

• E.

Explanation
The correct answer is e) volumul în grămadă. This is because when materials are in bulk, they do not occupy a fixed volume and can be piled up or compacted together, resulting in a volume that is measured as the volume in a heap or pile.

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• 5.

### 5. Spaţiul ocupat de substanţa solidă dintr-un corp determină:

• A.

A) masa corpului;

• B.

B) greutatea corpului;

• C.

C) volumul real al corpului;

• D.

D) volumul aparent al corpului;

• E.

C. C) volumul real al corpului;
Explanation
The correct answer is c) volumul real al corpului. The question is asking about the relationship between the space occupied by a solid substance in a body and a specific characteristic of the body. The volume of a solid substance refers to the amount of space it occupies, so the space occupied by the substance determines the volume of the body. Therefore, the correct answer is c) volumul real al corpului, which means the real volume of the body.

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• 6.

### 6. In cazul metodei volumului de lichid dizlocuit, in urma determinărilor de laborator se măsoară:

• A.

A) masa pulberii din biuretă;

• B.

B) volumul pulberii din biuretă;

• C.

C) volumul scurs din biuretă;

• D.

D) volumul initial si final din cilindrul gradat;

• E.

E) masa după parafinare.

D. D) volumul initial si final din cilindrul gradat;
Explanation
The correct answer is d) volumul initial si final din cilindrul gradat. This is because the method of volumul de lichid dizlocuit, or the displacement method, involves measuring the initial and final volumes in a graduated cylinder. This method is commonly used to determine the volume of a solid object by measuring the change in volume of a liquid when the object is submerged in it. By measuring the initial and final volumes in the graduated cylinder, the volume of the solid object can be calculated.

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• 7.

### 7. Metoda picnometrului este utilizată pentru determinarea:

• A.

A) volumului real pentru corpuri compacte cu formă geometrică regulată;

• B.

B) volumului real pentru corpuri compacte cu formă geometrică neregulată;

• C.

C) volumul materialelor sub forma de pulbere;

• D.

D) volumul materialelor poroase cu formă geometrică regulată;

• E.

E) volumul materialelor poroase cu formă geometrică neregulată;

C. C) volumul materialelor sub forma de pulbere;
Explanation
The picnometer method is used for determining the volume of materials in the form of powder. This method involves measuring the mass of a known volume of the powder and then calculating the density using the formula density = mass/volume. Since the volume of powders cannot be easily measured directly, the picnometer method provides a way to indirectly determine their volume by measuring the mass and density. Therefore, option c) is the correct answer.

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• 8.

### 8. Metoda parafinării combinată cu metoda volumului de lichid dizlocuit este utilizată pentru determinarea:

• A.

A) volumului real pentru corpuri compacte cu formă geometrică regulată;

• B.

B) volumului real pentru corpuri compacte cu formă geometrică neregulată;

• C.

C) volumul materialelor sub forma de pulbere;

• D.

D) volumul materialelor poroase cu formă geometrică regulată;

• E.

E) volumul materialelor poroase cu formă geometrică neregulată;

E. E) volumul materialelor poroase cu formă geometrică neregulată;
Explanation
The combination of the paraffin method and the liquid displacement method is used to determine the volume of porous materials with irregular geometric shapes. This method involves immersing the material in paraffin to fill the pores and then measuring the displacement of liquid when the material is submerged. This allows for an accurate measurement of the volume of the porous material, even if it does not have a regular geometric shape.

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• 9.

### 9. Metoda volumului de lichid dizlocuit este utilizata pentru determinarea:

• A.

A) volumului real pentru corpuri compacte cu formă geometrică regulată;

• B.

B) volumului real pentru corpuri compacte cu formă geometrică neregulată;

• C.

C) volumul materialelor sub forma de pulbere;

• D.

D) volumul materialelor poroase cu formă geometrică regulată;

• E.

E) volumul materialelor poroase cu formă geometrică neregulată;

B. B) volumului real pentru corpuri compacte cu formă geometrică neregulată;
E. E) volumul materialelor poroase cu formă geometrică neregulată;
Explanation
The correct answer is b) volumului real pentru corpuri compacte cu formă geometrică neregulată; and e) volumul materialelor poroase cu formă geometrică neregulată. The method of displaced liquid volume is used to determine the real volume of objects with irregular geometric shapes and the volume of porous materials with irregular geometric shapes. This method involves measuring the volume of liquid displaced when the object or material is submerged in a container of liquid. Since irregularly shaped objects and porous materials cannot be easily measured using traditional methods, this method provides an accurate way to determine their volume.

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• 10.

### 10. In cazul metodei picnometrului, in urma determinărilor de laborator, se măsoară:

• A.

A) masa pulberii din biuretă;

• B.

B) volumul pulberii din biuretă;

• C.

C) volumul scurs din biuretă;

• D.

D) volumul initial si final din cilindrul gradat;

• E.

E) masa după parafinare.

C. C) volumul scurs din biuretă;
Explanation
The correct answer is c) volumul scurs din biuretă. In the picnometer method, the volume of liquid that is drained from the burette is measured. This measurement is important in determining the density of the liquid being tested. By measuring the volume of liquid that is drained, one can calculate the density by dividing the mass of the liquid by its volume. Therefore, measuring the volume scoured from the burette is a crucial step in the picnometer method.

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• 11.

### 11. Volumul aparent pentru un corp poros cu formă geometrică neregulată se calculează cu relaţia:

• A.

A) V = L x l x h;

• B.

B) Va = L x l x h;

• C.

C) V = 25 – Vs;

• D.

D) V = Vf – Vi;

• E.

E) Va = Vf – Vi - m2-m1/Pp

E. E) Va = Vf – Vi - m2-m1/Pp
Explanation
The correct answer is e) Va = Vf – Vi - m2-m1/Pp. This equation calculates the apparent volume for a porous body with an irregular geometric shape. It takes into account the final volume (Vf), the initial volume (Vi), and the difference in mass (m2-m1) divided by the density of the fluid (Pp). This equation considers the changes in volume and mass to determine the apparent volume of the porous body.

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• 12.

### 12. Pentru un material aflat în stare de vrac se determină:

• A.

A) densitatea aparentă;

• B.

B) densitatea reala;

• C.

C) densitatea in stivă;

• D.

D) densitatea în grămadă în stare afanată;

• E.

E) densitatea în grămadă în stare îndesată.

D. D) densitatea în grămadă în stare afanată;
E. E) densitatea în grămadă în stare îndesată.
Explanation
The correct answer is d) densitatea în grămadă în stare afanată; and e) densitatea în grămadă în stare îndesată. This is because when a material is in a loose or bulk state, it has a lower density compared to when it is compacted or densely packed. The density in a loose state is called "densitatea în grămadă în stare afanată" and the density in a compacted state is called "densitatea în grămadă în stare îndesată". These terms refer to the different levels of compaction or packing of the material, which affects its density.

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• 13.

### 13. Volumul aparent pentru un corp poros cu formă geometrică regulată se calculează cu relaţia:

• A.

A) V = L x l x h;

• B.

B) Va = L x l x h;

• C.

C) V = 25 – Vs; Vf – Vi;

• D.

D) V =

• E.

E) Va = Vf – Vi - m2-m1/Pp

B. B) Va = L x l x h;
Explanation
The correct answer is b) Va = L x l x h. This formula calculates the apparent volume for a porous body with a regular geometric shape. The variables L, l, and h represent the length, width, and height of the body respectively. By multiplying these three dimensions together, we can determine the apparent volume of the body.

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• 14.

### 14. Volumul real pentru un corp compact cu formă geometrică regulată se calculează cu relaţia:

• A.

A) V = L x l x h;

• B.

B) Va = L x l x h;

• C.

C) V = 25 – Vs;

• D.

D) V = Vf – Vi;

• E.

E) Va = Vf – Vi - m2-m1/Pp

A. A) V = L x l x h;
Explanation
The correct answer is a) V = L x l x h. This formula calculates the volume of a compact body with a regular geometric shape. The variables L, l, and h represent the length, width, and height of the body respectively. By multiplying these three dimensions together, we can find the volume of the body.

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• 15.

### 15. Volumul real pentru un corp cu formă geometrică neregulată se calculează cu relaţia:

• A.

A) V = L x l x h;

• B.

B) Va = L x l x h;

• C.

C) V = 25 – Vs;

• D.

D) V = Vf – Vi;

• E.

E) Va = Vf – Vi - m2-m1/Pp

D. D) V = Vf – Vi;
Explanation
The correct answer is d) V = Vf - Vi. This equation represents the calculation of the real volume for an irregularly shaped object. "Vf" represents the final volume, while "Vi" represents the initial volume. By subtracting the initial volume from the final volume, we can determine the actual volume of the object.

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• 16.

### 16. Pentru un material compact se determină:

• A.

A) densitatea aparentă;

• B.

B) densitatea reala;

• C.

C) densitatea in stivă;

• D.

D) densitatea în grămadă în stare afanată;

• E.

E) densitatea în grămadă în stare îndesată.

B. B) densitatea reala;
Explanation
The correct answer is b) densitatea reala. Densitatea reala se refera la masa unei unitati de volum a unui material compact. Aceasta masoara cat de multa masa este concentrata intr-un anumit volum al materialului. Densitatea reala se calculeaza impartind masa materialului la volumul ocupat de acesta.

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• 17.

### 17. Masa unităţii de volum determină:

• A.

A) greutatea unui corp;

• B.

B) densitatea corpului;

• C.

C) greutatea specifică;

• D.

D) porozitatea;

• E.

E) compactitatea.

B. B) densitatea corpului;
Explanation
The correct answer is b) densitatea corpului. The unit of volume determines the density of a body. Density is defined as the mass of an object divided by its volume. Therefore, the unit of volume is directly related to the determination of an object's density.

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• 18.

### 18. Volumul real in cazul unui material sub formă de pulbere, utilizand metoda picnometrului, se determină cu relaţia:

• A.

A) V = L x l x h;

• B.

B) Va = L x l x h;

• C.

C) V = 25 – Vs;

• D.

D) V = Vf – Vi;

• E.

E) Va = Vf – Vi - m2--m1/Pp

C. C) V = 25 – Vs;
• 19.

### 19. Pentru un material poros de determină:

• A.

A) densitatea aparentă;

• B.

B) densitatea reala;

• C.

C) densitatea in stivă;

• D.

D) densitatea în grămadă în stare afanată;

• E.

E) densitatea în grămadă în stare îndesată.

A. A) densitatea aparentă;
Explanation
The question asks for the determination of the density of a porous material. The correct answer is option a) densitatea aparentă, which translates to apparent density. Apparent density refers to the mass of a material divided by its total volume, including the volume of any pores or voids within the material. This is the appropriate measure of density for a porous material as it takes into account the empty spaces within it.

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• 20.

### 20. Volumul în grămadă pentru un material aflat în vrac se calculează cu relaţia:

• A.

A) L x l x h;

• B.

B) Vf – Vi;

• C.

C) Vf – Vi – Vp;

• D.

D) V + Vp + V gol;

• E.

E) 25- Vs.

D. D) V + Vp + V gol;
Explanation
The correct answer is d) V + Vp + V gol. This formula calculates the volume of a material in bulk. V represents the volume of the material, Vp represents the volume of any voids or air pockets within the material, and V gol represents the volume of any empty spaces or gaps. By adding these three components together, we can determine the total volume of the material in bulk.

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• 21.

### 21. Greutatea unităţii de volum determină:

• A.

A) volumul de goluri;

• B.

B) compactitatea;

• C.

C) densitatea;

• D.

D) greutatea specifică;

• E.

E) porozitatea.

D. D) greutatea specifică;
Explanation
The correct answer is d) greutatea specifică. Greutatea specifică refers to the weight of a unit volume of a substance. It is a measure of how heavy a material is compared to its volume. It is commonly used in engineering and construction to determine the strength and stability of structures.

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• 22.

### 22. Relatia G/V determina:

• A.

A) compactitatea;

• B.

B) porozitatea;

• C.

C) densitatea;

• D.

D) greutatea specifica;

• E.

E) volumul de goluri.

D. D) greutatea specifica;
Explanation
The relationship G/V determines the specific weight.

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• 23.

### 23. Relaţia  m/V determina:

• A.

A) compactitatea;

• B.

B) porozitatea;

• C.

C) densitatea;

• D.

D) greutatea specifica;

• E.

E) volumul de goluri.

C. C) densitatea;
Explanation
The relationship m/V refers to the ratio of mass to volume, which is known as density. Density is a measure of how much mass is contained within a given volume. Therefore, the correct answer is c) densitatea.

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• 24.

### 24. Un material poros se caracterizeaza prin:

• A.

A) C < 1;

• B.

B) C = 1

• C.

C) n > 1;

• D.

D) n < 1;

• E.

E) n = 0.

A. A) C < 1;
Explanation
A porous material is characterized by a porosity factor, denoted as C. The porosity factor represents the ratio of the volume of voids or pores in the material to the total volume of the material. A value of C less than 1 indicates that the volume of voids is less than the total volume, meaning that the material is not fully porous. Therefore, option a) C < 1 is the correct answer.

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• 25.

### 25. Gradul de umplere al volumului aparent cu material solid determină:

• A.

A) volumul de goluri;

• B.

B) compactitatea;

• C.

C) densitatea;

• D.

D) greutatea specifică;

• E.

E) porozitatea.

B. B) compactitatea;
Explanation
The correct answer is b) compactitatea. The degree of filling of the apparent volume with solid material determines the compactness or density of the material. A higher degree of filling indicates a more compact material, while a lower degree of filling indicates a less compact material.

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• 26.

### 26. Relatia V/Va sau Pa/P determina:

• A.

A) compactitatea;

• B.

B) porozitatea;

• C.

C) densitatea;

• D.

D) greutatea specifica;

• E.

E) volumul de goluri.

A. A) compactitatea;
Explanation
The relationship V/Va or Pa/P determines the compactness of a substance. Compactness refers to how closely packed the particles or molecules are in a given volume. A higher V/Va or Pa/P value indicates a higher compactness, meaning that the substance has less empty space or voids between its particles. Conversely, a lower V/Va or Pa/P value indicates a lower compactness, meaning that the substance has more empty space or voids between its particles. Therefore, the correct answer is a) compactness.

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• 27.

### 27. Gradul de umplere cu pori ai volumului total determină:

• A.

A) volumul de goluri;

• B.

B) compactitatea;

• C.

C) densitatea;

• D.

D) greutatea specifică;

• E.

E) porozitatea.

E. E) porozitatea.
Explanation
The correct answer is e) porozitatea. The question is asking about the factor that determines the degree of pore filling in the total volume. Porosity refers to the percentage of void space in a material, and it is directly related to the volume of pores. Therefore, the degree of pore filling, or porosity, is determined by the volume of pores in the total volume.

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• 28.

### 28. Relatia Vp/Va determina:

• A.

A) compactitatea;

• B.

B) porozitatea;

• C.

C) densitatea;

• D.

D) greutatea specifica;

• E.

E) volumul de goluri.

B. B) porozitatea;
Explanation
The relationship between Vp/Va determines the porosity of a material. Porosity refers to the amount of empty space or voids within a material. Vp represents the volume of pores or voids in the material, while Va represents the total volume of the material. By comparing the volume of pores to the total volume, we can determine the porosity of the material. Therefore, the correct answer is b) porosity.

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• 29.

### 29. Totalitatea spaţiilor existente între granulele care formează o grămadă determină:

• A.

A) volumul de goluri;

• B.

B) compactitatea;

• C.

C) densitatea;

• D.

D) greutatea specifică;

• E.

E) porozitatea.

A. A) volumul de goluri;
Explanation
The correct answer is a) volumul de goluri. The spaces between the grains in a pile determine the volume of voids or empty spaces within the pile. This is important in understanding the overall structure and density of the pile.

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• 30.

### 30. Un material compact se caracterizeaza prin:

• A.

A) C < 1;

• B.

B) C = 1;

• C.

C) n > 1;

• D.

D) n < 1;

• E.

E) n = 0;

B. B) C = 1;
E. E) n = 0;
Explanation
A compact material is characterized by a coefficient of compressibility (C) equal to 1, meaning that it does not compress under pressure. Additionally, it is characterized by a porosity (n) equal to 0, indicating that it is completely solid without any empty spaces or pores.

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• 31.

### 31. In cazul unui material cu masa initială (mu)umedă , cu relatia mu-m/mu 100 % se poate determina:

• A.

A) umiditatea relativă;

• B.

B) umiditatea absoluta;

• C.

C) absorbtia de apă în masă;

• D.

D) absorbţia de apă în volum;

• E.

E) capilaritatea.

A. A) umiditatea relativă;
Explanation
The correct answer is a) umiditatea relativă. The given equation mu-m/mu represents the relative humidity of a material with initial wet mass. Relative humidity is a measure of the amount of moisture present in the air compared to the maximum amount it can hold at a given temperature. In this case, the equation compares the difference between the initial wet mass (mu) and the final mass (m) of the material, allowing us to determine the relative humidity.

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• 32.

### 32. In cazul unui material cu umiditate 0% in stare naturala, cu relatia mu-m/Va 100 % se poate calcula:

• A.

A) umiditatea relativă;

• B.

B) umiditatea absoluta;

• C.

C) absorbtia de apă în masă;

• D.

D) absorbţia de apă în volum;

• E.

E) capilaritatea.

D. D) absorbţia de apă în volum;
Explanation
The given answer is d) absorbţia de apă în volum because the relationship mu-m/Va is used to calculate the water absorption in volume. This relationship represents the ratio between the mass of water absorbed (m) and the volume of the material (Va). Therefore, it is used to determine the amount of water that can be absorbed by a material in its natural state with 0% moisture content.

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• 33.

### 33. Cantitatea de apa pe care un material o absoarbe si retine in pori si capilare determina:

• A.

A) capilaritatea;

• B.

B) hidroscopicitatea;

• C.

C) umiditatea materialului;

• D.

D) absorbtia de apa;

• E.

E) gelivitatea.

D. D) absorbtia de apa;
Explanation
The correct answer is d) absorbtia de apa. This is because the quantity of water that a material absorbs and retains in its pores and capillaries is directly related to its ability to absorb water. The term "absorbtia de apa" refers specifically to the process of water absorption by a material.

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• 34.

### 34. Cantitatea de apa legata fizic ce se afla la un moment dat in material determina:

• A.

A) capilaritatea;

• B.

B) hidroscopicitatea;

• C.

C) umiditatea materialului;

• D.

D) absorbtia de apa;

• E.

E) gelivitatea.

C. C) umiditatea materialului;
Explanation
The correct answer is c) umiditatea materialului. This is because the amount of water physically bound in a material at a given time determines its moisture content or humidity. The more water present in the material, the higher the humidity or moisture content.

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• 35.

### 35. In cazul unui material cu umiditate 0% in stare naturala, cu relatia mu-m/m 100 % se poate calcula:

• A.

A) umiditatea relativă;

• B.

B) umiditatea absoluta;

• C.

C) absorbtia de apă în masă;

• D.

D) absorbţia de apă în volum;

• E.

E) capilaritatea.

C. C) absorbtia de apă în masă;
Explanation
The given question is in Romanian and it asks about the calculation that can be done when the moisture content of a material is 0% in its natural state with a mu-m/m relationship of 100%. The correct answer, "c) absorbtia de apă în masă," translates to "absorption of water in mass." This suggests that when the moisture content is 0% and the mu-m/m relationship is 100%, it is possible to calculate the mass of water absorption.

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• 36.

### 36. In cazul unui material cu masa iniţială (mu) umedă, si masa finală (m), cu relatia mu-m/m 100 % se poate calcula:

• A.

A) umiditatea relativă;

• B.

B) umiditatea absoluta;

• C.

C) absorbtia de apă în masă;

• D.

D) absorbţia de apă în volum;

• E.

E) capilaritatea.

B. B) umiditatea absoluta;
Explanation
The correct answer is b) umiditatea absoluta. The formula mu-m/m 100% is used to calculate the absolute humidity of a material with initial wet mass (mu) and final mass (m). This formula measures the amount of water vapor present in a substance, regardless of its volume or relative humidity. Therefore, the correct answer is umiditatea absoluta (absolute humidity).

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• 37.

### 37. Proprietatea materialelor de a lăsa să treacă o anumită cantitate de apă printr-o suprafaţă determinată, într-un interval de timp dat, la  presiune şi temperatură constantă, determină:

• A.

A) permeabilitatea la apă;

• B.

B) permeabilitatea la aer;

• C.

C) permeabilitatea la vapori;

• D.

D) capilaritatea;

• E.

E) gelivitatea.

A. A) permeabilitatea la apă;
Explanation
The given correct answer, a) permeabilitatea la apă, is the most fitting explanation for the question. The question asks about the property of materials that allows a certain amount of water to pass through a specific surface in a given time interval, at constant pressure and temperature. This property is known as permeability to water. The other options, such as permeability to air, permeability to vapors, capillarity, and frost resistance (gelivitatea), do not directly relate to the described property of allowing water to pass through a surface. Therefore, the correct answer is a) permeabilitatea la apă.

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• 38.

### 38. Coeficientul de înmuiere al materialelor se determină cu relaţia:

• A.

A) Rumed/Ruscat;

• B.

B) Ruscat/Rumed;

• C.

C) (R1-R2)/R1;

• D.

D) R1/(R1-R2);

• E.

E) (m1-m2)/m1.

A. A) Rumed/Ruscat;
Explanation
The correct answer is a) Rumed/Ruscat. The coefficient of friction is determined by dividing the force of friction (Rumed) by the normal force (Ruscat). This ratio gives us a measure of how difficult it is to slide one object over another.

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• 39.

### 39. Proprietatea materialelor de a lăsa să treacă o anumită cantitate de aer printr-o suprafaţă determinată, într-un interval de timp dat, la  presiune şi temperatură constantă, determină:

• A.

A) permeabilitatea la apă;

• B.

B) permeabilitatea la aer;

• C.

C) permeabilitatea la vapori;

• D.

D) capilaritatea;

• E.

E) gelivitatea.

B. B) permeabilitatea la aer;
Explanation
The given question is asking about the property of materials to allow a certain amount of air to pass through a specific surface in a given time interval, at constant pressure and temperature. This property is known as permeability to air. Therefore, the correct answer is b) permeabilitatea la aer.

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• 40.

### 40. La elementele portante care lucrează în mediu umed, coeficientul de înmuiere trebuie să îndeplinească condiţia:

• A.

A) K >= 1;

• B.

B) K >= 0,95;

• C.

C) K >= 0,90;

• D.

D) K >= 0,8 0;

• E.

E) K < 0,80.

D. D) K >= 0,8 0;
Explanation
The correct answer is d) K >= 0,8 0. This means that the coefficient of softening for load-bearing elements working in a wet environment must be greater than or equal to 0.80. This condition ensures that the load-bearing elements can withstand the moisture and remain structurally stable.

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• 41.

### 41 Materialele vitrificate se caracterizează prin:

• A.

A) n < 2%;

• B.

B) n < 7%;

• C.

C) n < 8%;

• D.

D) n < 9%;

• E.

E) n < 10%;

A. A) n < 2%;
Explanation
Vitrified materials are characterized by a water absorption rate of less than 2%. This means that these materials have a very low porosity, which makes them highly resistant to water absorption. The low water absorption rate also indicates that vitrified materials are less likely to be damaged or stained by water or other liquids. This property makes vitrified materials ideal for use in areas where moisture or liquid exposure is common, such as bathrooms, kitchens, or outdoor spaces.

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• 42.

### 42. Proprietatea materialelor saturate cu apă de a rezista la actiunea repetată a îngheţului şi dezgheţului determină:

• A.

A) permeabilitatea la apă;

• B.

B) permeabilitatea la aer;

• C.

C) permeabilitatea la vapori;

• D.

D) capilaritatea;

• E.

E) gelivitatea.

E. E) gelivitatea.
Explanation
The ability of water-saturated materials to resist the repeated action of freezing and thawing is known as gelivitatea. This term specifically refers to the ability of materials to withstand the physical stresses caused by the expansion of water when it freezes and the subsequent contraction when it thaws. Gelivitatea is an important property to consider in construction and engineering projects, as materials that are not resistant to freezing and thawing can deteriorate and become structurally compromised over time.

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• 43.

### 43. Materialele clincherizate se caracterizează prin:

• A.

A) n < 2%;

• B.

B) n < 7%;

• C.

C) n < 8%;

• D.

D) n < 9%;

• E.

E) n< 10%.

C. C) n < 8%;
Explanation
Materialele clincherizate se caracterizează prin conținutul de azot (n) mai mic de 8%. This means that the nitrogen content in clincherized materials is less than 8%.

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• 44.

### 44. Proprietatea materialelor de a lăsa să treacă o anumită cantitate de vapori printr-o suprafaţă determinată, într-un interval de timp dat, la  presiune şi temperatură constantă, determină:

• A.

A) permeabilitatea la apă;

• B.

B) permeabilitatea la aer;

• C.

C) permeabilitatea la vapori;

• D.

D) capilaritatea;

• E.

E) gelivitatea.

C. C) permeabilitatea la vapori;
Explanation
The given correct answer for this question is c) permeabilitatea la vapori. This refers to the ability of materials to allow a certain amount of vapors to pass through a specific surface within a given time interval, at constant pressure and temperature. It is different from permeability to water (a), which refers to the ability of materials to allow water to pass through them, and permeability to air (b), which refers to the ability of materials to allow air to pass through them. Capillarity (d) refers to the ability of liquids to flow in narrow spaces against the force of gravity, and gelivitatea (e) refers to the susceptibility of materials to frost damage.

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• 45.

### 45. Temperatura la care un material se înmoaie sub greutatea proprie, determină:

• A.

A) punctul de inflamabilitate;

• B.

B) punctul de aprindere;

• C.

C) punctul de înmuiere;

• D.

D) refractaritatea;

• E.

E) punctul de topire.

C. C) punctul de înmuiere;
D. D) refractaritatea;
Explanation
The correct answer for this question is c) punctul de înmuiere; and d) refractaritatea. The temperature at which a material softens under its own weight is known as the "punctul de înmuiere" or the softening point. This is an important property to consider when determining the material's behavior under certain conditions. Refractoriness, on the other hand, refers to the ability of a material to withstand high temperatures without melting or deforming. Both of these properties are relevant when considering the behavior of a material under heat.

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• 46.

### 46. Temperatura la care concentraţia substanţelor organice (prin încălzire progresivă) a devenit destul de mare încat să se aprindă în contact cu o flacără, determină:

• A.

A) punctul de inflamabilitate;

• B.

B) punctul de aprindere;

• C.

C) punctul de înmuiere;

• D.

D) punctul de refractaritate;

• E.

E) punctul de topire.

B. B) punctul de aprindere;
Explanation
The correct answer is b) punctul de aprindere. This is because the question is asking for the temperature at which the concentration of organic substances becomes high enough to ignite when in contact with a flame. The punctul de aprindere, or flash point, is the lowest temperature at which a substance can vaporize to form an ignitable mixture in air.

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• 47.

### 47. Temperatura la care concentraţia substanţelor organice (prin încălzire progresivă) a devenit destul de mare încat să se aprindă în aer chiar şi în lipsa unei flacări, determină:

• A.

A) punctul de inflamabilitate;

• B.

B) punctul de aprindere;

• C.

C) punctul de înmuiere;

• D.

D) punctul de refractaritate;

• E.

E) punctul de topire.

A. A) punctul de inflamabilitate;
Explanation
The correct answer is a) punctul de inflamabilitate. The question asks for the temperature at which the concentration of organic substances becomes high enough to ignite in the air even without a flame. This is known as the flash point or the point of inflammability.

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• 48.

### 48. Un material care conţine un surplus de energie calorică o transmite prin:

• A.

A) conducţie;

• B.

B) convecţie;

• C.

• D.

D) penetraţie;

• E.

E) gelivitate.

A. A) conducţie;
B. B) convecţie;
Explanation

A material that contains an excess of thermal energy can transfer it through different methods. Conduction refers to the transfer of heat through direct contact between particles of the material. Convection involves the transfer of heat through the movement of a fluid, such as air or water. Radiation is the transfer of heat through electromagnetic waves. In this case, the material can transfer the excess thermal energy through all three methods: conduction, convection, and radiation.

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• 49.

### 49. Rezistenţa la transfer termic printr-un element de grosime d, este egala cu:

• A.

A) (d x b)/landa;

• B.

B) d/(b x landa);

• C.

C) (b x landa)/d;

• D.

D) (landa x b)/d;

• E.

E) landa/(b x d).

B. B) d/(b x landa);
Explanation
The correct answer is b) d/(b x landa). This answer is derived from the equation for thermal resistance, which is given by R = d/(kA), where R is the thermal resistance, d is the thickness of the element, k is the thermal conductivity, and A is the cross-sectional area of the element. In this case, the thermal conductivity (k) is represented by the Greek letter landa, and the cross-sectional area (A) is represented by b. Therefore, the correct answer is d/(b x landa).

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• 50.

### 50. Cantitatea de căldură ce trece printr-o suprafată de 1 m2 cu grosimea de 1m, în timp de 1h, la o diferenţă de temperatură de 1ºC, între feţele unui material omogen, determină:

• A.

A) rezistenţa la transfer termic;

• B.

B) căldura specifică;

• C.

C) conductivitatea termică;

• D.

D) capacitatea calorică;

• E.

E) coeficientul de dilatare liniară. Back to top